FAA-AM-80-7 

THE SELECTION OF AIR TRAFFIC CONTROL SPECIALISTS: 

I. HISTORY AND REVIEW OF CONTRIBUTIONS BY THE CIVIL AEROMEDICAL INSTITUTE 

Edited by: 

William E. Collins 

James 0. Boone 

Allan D. VanDeventer 

Civil Aeromedical Institute 

Federal Aviation Administration 

Oklahoma City , Oklahoma 

• 

~-

JUNE 1980 

Document is available to the public through the 

National Technical Information Service, 

Springfield, Virginia 22161 

Prepared for 

U.S. DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

Office of Aviation Medicine 

Washington, D.C. 20591 
NOTICE 

This document is disseminated under the sponsorship 

of the Department of Transportation in the interest 

of information exchange. The United States Government assumes no liability for its content or use 

thereof. 
1. Repo rt No . 2 . Government Accession No . 

FAA-AM-80- 7 

4. Title and Subtitle 

THE SELECTION OF AIR TRAFFIC CONTROL SPECIALISTS: 

I. HISTORY AND REVIEW OF CONTRIBUTIONS BY THE CIVIL 

AEROMEDICAL INSTITUTE 

Technical ~eport Documentation Page 

3. Recipient ' s Catalog No. 

S. Report Dote 

JUNE 1980 

6 . Performing Organization Code 

l--::----..,....-,.....,.,n-1.-.:::-.,--,---,---...,.,.......,...,....,.---....---,....-....,...~-:------------! 8 . Performing Organ i zoti on Report No . 

7. Author' s} Ed1ted by: Wi.Ll1am E. Coll1ns, 

James 0. Boone, and Allan D. VanDeventer 

9, Performing Orgoni zotion Nome and Address 

FAA Civil Aeromedical Institute 

P.O. Box 25082 

Oklahoma City, Oklahoma 73125 

10. Work Unit No . (TRAIS} 

11 . Contract or Grant No . 

~~~~~~~~~~~~~~~~~~~~~~~~~~ 13. Type of Report and Period Covered 

12. Sponsoring Agency Nome and Address 

Office of Aviation Medicine 

Federal Aviation 

800 Independence 

Washington, D.C. 

15. Supplementary Notes 

Administration 

Avenue, S.W. 

20591 

14 . Sponsoring Agency Code 

Work was performed under Task AM-C-80-PSY-74. 

16. Abstract 

For two decades the FAA Civil Aeromedical Institute (CAMI) has engaged in active 

research programs exploring most aspects of the problems of effectively selecting 

air traffic control specialists (ATCSs) for the FAA. The results of those efforts 

have contributed directly to the establishment of revised ATCS selection standards 

by the Civil Service Commission (CSC). Early studies on the validity of aptitude 

tests for predicting successful completion of Academy training led to a decision 

to use such tests for part of the CSC screening standard. Later studies led to the 

establishment of a maximum age standard of 30 years for entry into ATCS training. 

In addition, CAMI researchers have continuously evaluated the validity of 

existing standards, have examined numerous variables and alternative aptitude 

measures, and ~ave provided a number of data-based recommendations in an effort to 

upgrade the effectiveness of predicting success in ATCS training. This paper 

reviews that research with emphasis on aptitude screening measures, attrition, 

age, prior experience, education, sex, military ATCS training, and the Uniform 

Guidelines on Employee Selection. 

17, Key Words 18. Distribution Statement 

Air Traffic Control Specialists 

Personnel Selection 

Document is available to the public througt 

the National Technical Information Service, 

Springfield, Virginia 22161. 

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No, of Pages 22. Price 

Unclassified Unclassified 53 

Form DOT F 1700.7 (8-72} Reproduction of completed page authorized 

• 
FOREWORD 

This report was prepared at the request of the FAA Office 

of Aviation Medicine to serve as one of several sources 

documenting various aspects of research on the selection of 

air traffic control specialists (ATCSs). It is largely based 

on work accomplished by Bart B. Cobb (now deceased), whose 

published studies and unpublished mini-studies (memorandum 

reports both to FAA officials in personnel and training and to 

representatives of the Civil Service Commission (CSC--now the 

Office of Personnel Management)) spanned over a decade and a 

half; that work contributed significantly to FAA-CSC decisions 

regarding ATCSs and has been a prime source for contractors 

doing FAA-sponsored research on the air traffic control 

occupation. To the extent possible, much of the material 

was compiled directly from Cobb's writings, albeit reorganized 

and updated, with minimal editing; he would have preferred it 

that way. Similar treatment was accorded the work of 

W. Dean Chiles (also deceased) with regard to the section on 

the Multiple Task Performance Battery. Although the emphasis 

in this review is on Cobb's formidable contributions, that 

emphasis is not intended to obscure either the significant 

contributions of David K. Trites, with whom Cobb collaborated 

during 1960-65, or the more recent analytic work at the 

Civil Aeromedical Institute by Mary A. Lewis (now with PPG 

Industries, Inc.), James 0. Boone, and Allan D. VanDeventer, 

the impact of whicn is still too fresh to place definitively 

in a historical perspective. 

ACKNOWLEDGEMENT 

We gratefully acknowledge the assistance of· Jo Ann Steen, 

Lena Dobbins, and Marcia Grimm in the preparation of this 

manuscript. 
TABLE OF CONTENTS 

History of Civil Aeromedical Institute Selection Research 

and Related Civil Service Commission Standards •••••••••••••••••• 

Revised Aptitude-Screening Procedures ••••••••••••••••••••••••• 

Programs Designed to Aid Minorities and Women in ATCS 

Selection and Training ••••••••••••••••••••••••••• 

Current Status of Selection Standards •••••••••••••. 

Summary .........••••••.•.•.•.•...•••..•...•.••••••• 

Some Followup Studies on Attrition •••••••••••••••••••••••••••••••• 

Surrunary ••••••••••••••••••••••••••••••••••••••••••••••••••••••• 

Age as a Selection Factor •••••••••••••••••• 

Summary •••••••••••••••••••••••••••••••• 

Page 

l 

7 

10 

12 

l3 

14 

20 

20 

22 

Aviation-Related Experience as a Selection Factor ••••••••••••••••• 25 

Summary . . . . • . . . . . . . . • • • . . . . . . • • . . . . . • • • . . • . • . . • • • • • • • . • . • • • • • • 3 0 

Education as 

Summary 

a Selection Factor 

Sex as a Factor in Performance and Attrition ••••••••••••••••• 

Summary •...•.•...•...•.••....•.........•....••••••....... 

Research on Military ATCS Trainees 

Summary 

Research on Alternative Aptitude Screening Measures 

The Directional Headings Test •••••••••••••••••• 

The Multiple Task Performance Battery •••••••••• 

Summary 

Research Related to the Uniform Guidelines on Employee 

Selection . . . . . . . . . . . . . . ............................. . 

Summary 

References 

30 

34 

34 

36 

36 

38 

38 

39 

41 

45 

45 

47 

49 

THE SELECTION OF AIR TRAFFIC CONTROL SPECIALISTS: 

I. HISTORY AND REVIEW OF CONTRIBUTIONS BY THE 

CIVIL AEROMEDICAL INSTITUTE 

History of Civil Aeromedical Institute Selection Research 

and Related Civil Service Commission Standards 

Eligibility for Air Traffic Control Specialist (ATCS) training with the 

Federal Aviation Administration (F~~) has traditionally included 

consideration of an applicant's preemployment experience, educational 

background, the outcome of an interview with management officials, and the 

results of a medical examination. Previous relevant experience, 

particularly in military air traffic control, has always been heavily 

weighted in the selection process. Experience as a pilot and various types 

of previous work in communications and air surveillance have also been 

consistently viewed as important assets. In general, however, ATCS 

selection programs prior to t962 involved no formal assessment of mental 

abilities or aptitudes (t7). 

Historically, research on ATCS selection is rooted in a l9SO contract 

by the Civil Aeronautics Administration (CAA--precursor to the FAA) for the 

development of aptitude tests that could be used to select ATCS trainees. 

The results of that contracted study (i) indicated that aptitude tests 

potentially could make an effective contribution in the selection process 

and (ii) provided the format for an Air Traffic Problems (ATP) test (SO). 

In t9S6, Brokaw of the United States Air Force's Personnel Laboratory, 

in a joint effort with the CAA, administered a large number of aptitude 

tests to t97 ATCS trainees. His findings (8) indicated that a composite 

aptitude test score formed by adding together scores on tests of arithmetic 

reasoning, symbolic reasoning, code translation, and the ATP test could 

effectively predict instructors' ratings of training performance and 

supervisors' ratings of job performance approximately a year after training. 

Then in t9S9, a number of AT~S trainees were recruited on an 

experimental basis using the Federal Service Entrance Examination. For a 

variety of reasons, the results of that experiment were considered 

inconclusive (SO). 

1 
A continuing research program on ATCS selection began in 19SO with the 

establishment of the FAA Civil Aeromedical Research Institute (now the Civil 

Aeromedical Institute--CAMI) in O~lahoma City, Oklahoma. The first study 

(46) was a followup of the 197 trainees tested by Brokaw in 1956. Job 

performance ratings were obtained by Trites (46) from supervisors of 143 of 

the former trainees; the vast majority of the latter were fully qualified 

ATCSs. To evaluate the effectiveness of the aptitude tests recommended by 

Brokaw, the 143 men wer'e classified as either satisfactory or marginal in 

their job performance as determined from the ratings and comments of their 

supervisors. The distribution of the composite scores based on the four 

aptitude tests given each trainee in 1955 was divided into fourths and the 

percentages of satisfactory and marginal individuals in each fourth were 

computed (see Figure 1). Scores achieved on the aptitude tests given at the 

beginning of training were clearly related to job performance evaluations 

obtained 4 to 5 years after training. 

SCORE 

RANGE 

~106 

97-105 

84-96 

~83 

SATISFACTORY 

I I 

78 Cfo 

63 Cfo 

58 Cfo 

~~ 

50 Cfo X: 

MARGINAL 

N 

36 

35 

~~ ~ ·' " "><' 

;x; 42 Cfo 36 

'X'> 

» :Xt>< t>OQo 

?¢< » . 

~~ 50 Cfo ?<,: X. 36 

:X ~X? )6( ;;<; ---

143 

Figure 1. Percentages of marginal and satisfactory ATCSs in 

approximate fourths of composite aptitude test 

scores predicted from an early regression equation 

(from Trites and Cobb, 1964, ref. 50). 

Concurrently with the collection of the facility performance data on 

the trainees tested in 1956, extensive experimental psychological testing of 

all En Route and Terminal trainees who entered the. FAA Academy in O~lahoma 

City for basic ATCS training was begun in August 1960 (50). All of these 

trainees had been selected by medical and experience requirements and none 

by aptitude tests. The group of commercially available tests with which 

experimentation was started required 8 hours for administration. It 

2 
comprised those tests previously found most useful for prediction of ATCS 

training and job performance plus tests of a number of aptitude areas not 

previously examined. The tests yielded 44 different scores. Many of these 

tests were either commercially published instruments or aptitude assessment 

devices developed under contractual arrangement for the FAA. In fact, no 

Civil Service Commission (CSC--now known as the Office of Personnel 

Management, OPM) tests were included in the research prior to July t961 

(t7). By that time a series of multiple-regression analyses, accomplished 

by Cobb and Trites in connection with followup studies of several hundred 

men, had identified a total of 8 tests (from a group of 27) from which a 

variety of summary measures having validity for prediction of ATCS trainee 

performance might be derived. Seven of the eight tests were commercially 

published instruments; the remaining one was the contractually developed 

ATP test. 

While the seven published instruments of that experimental battery are 

referred to as "tests," they were actually parts, or subtests, taken from 

rather lengthy and comprehensive aptitude-measuring devices (t7). Three of 

the seven were subtests of the Psychological Corporation's Differential 

Aptitude Test (DAT), viz, DAT Space Relations, DAT Numerical Ability, and 

DAT Abstract Reasoning. The first test measures the ability of an examinee 

to visualize objects and forms in two or .three dimensions, the second is a 

test of arithmetical or computational skill, while the third provides a 

measure of nonverbal reasoning (specifically, determining, for each item, 

which of a series of choices (figures) properly carries out a principle of 

logical development exhibited by a sequence of figures). The remaining four 

were subtests of the California Test Bureau's Test of Mental Maturity (CTill1, 

Advanced Form A Edition)(~S). In each item of CTMM Analogies, the examinee 

must recognize the relationship between a pair of drawings (objects) in 

order to identify, by analogy, one of four choices as being similarly 

related to a third. CTMM Inference involves the comprehension of statements 

that present premises underlying the derivation of logical conclusions. The 

subtest designated as CTMM Numerical Quantity-Arithmetic measures the 

ability to solve word-presented arithmetic problems, while CTMM Numerical 

Quantity-Coins involves the mental manipulation of interrelated amounts of 

money and numbers of coins. 

No single group of trainees was ever administered all eight tests (the 

seven commercial tests plus Air Traffic Problems)~ one class was examined 

with seven, and several successive classes were administered either six or 

five, of the eight instruments (t7). When an average of the academic and 

laboratory grades was computed for each Academy trainee and ~loyed as the 

criterion, the validities of the composite measures, derived from the 

performance scores on five, six, or seven tests, were found to range from 

.35 to .54 (Pearson product-moment coefficients). More importantly, an 

analysis revealed that about 70 to 80 percent of the cases classified as 

training-course failures were, in most instances, represented in the lower 

half of the distribution of scores derived with each respective group of 

tests. Moreover, the Academy attrition rates were averaging over 30 percent 

despite the fact that most trainees were former military controllers. 

3 
The potential value of the tests for screening purposes was thus 

recognized, and, when similar results were obtained with additional samples, 

the FAA and the CSC agreed that aptitude-test measures should be employed on 

a tentative basis in the selection of some of the nonexperienced applicants 

(l7). However, commercially published tests could not be used because such 

instruments were deemed more susceptible to compromise than those subjected 

to rigid CSC control procedures. Commission officials therefore examined 

their extensive file of esc tests and selected several instruments that, in 

terms of factor content, appeared to approximate a number of the validated 

commercial tests. Since the ATP test had been developed specifically for 

the FAA and was still completely controlled, it was officially adopted as a 

CSC test. In addition, CAMI researchers were provided a number of other CSC 

tests, to administer and evaluate. 

Commencing in August l96l, all incoming classes of Academy ATCS 

trainees were experimentally assessed with the entire group of tests 

extracted from the CSC files and with the ATP test. The restricted time 

available for each testing session precluded an examination of each class 

with the complete and previously validated battery of commercial tests. 

However, time beyond that required for the CSC tests was available to permit 

administration of a portion of the commercial battery. followup studies of 

Academy trainees examined with the revised battery during the next tO months 

revealed that composite scores based on five of the CSC tests and the ATP 

test could be used effectively to predict training outcomes (17). Composite 

scores of 190 and higher were attained by approximately 55 percent of all 

the examinees. Of these, about 70 percent successfully completed their 

training course and were certificated as ATCSs. In contrast, almost 75 

percent of those with scores of 189 and lower failed to graduate and were 

eliminated from further FAA training (l7). These results approximated those 

obtained in earlier analyses (with other groups) for the "commercial 

seven-test composite." Three of the tests involved in the six-test CSC 

composite were those that had been selected as "counterparts" of three 

commercial tests; these instruments provided measures of numerical, 

spatial, and nonverbal abstract-reasoning abilities. The new composite also 

included the ATP test (an extensive revision of the original test), an 

instrument known as Letter ·sequence (a new test, not identified in the 

original research, which measured reasoning ability), and a test of 

following oral directions. The CSC battery is commonly referred to as "The 

CSC ATC Aptitude Screening Test" and its six elements as "subtests" (see 

Table l). 

Although CAMI was requested to continue its experimental testing 

program and obtain additional validation data (including, now, flight 

Service Station (FSS) ATCS trainees for whom no previous experimental data 

were available), an early analysis, in which the aptitude tes.t scores of the 

first 302 examinees were validated against the Academy training criteria, 

yielded findings (highly similar to those later obtained for the complete 

sample) that prompted CSC and FAA officials to authorize use of the battery, 

beginning in July 1962, in screening only those applicants unable to 

establish training eligibility in terms of the normally prescribed 

4 
VI 

CSC Subtest 

esc 24 

Computations 

esc 51 

Spatial Patterns 

esc 135 

Table 1. Description qf esc ATC Aptitude Screening Test Variables 

(from Cobb, Lay, & Bourdet, 1971, ref. 18) 

Weight 

2 

Description 

A highly speeded test of arithmetic skill. The proble

addition, subtraction, multiplication, and division. 

is referred to as "numeri ca 1 facility." 

A test consisting of two different types of spatial it

the task is to identify solid figures that can be made 

patterns. In each of the other, three different views 

presented and the subject must select the correct obje

alternatives. 

Following Oral Directions 

In this test the subject must listen carefully to ora

tions and information; then discriminate between relev

information in order to proceed ioward the proper solu

simple tasks. 

esc 157 

Abstract Reasoning 

and 

Letter Sequence 

esc 540 

esc Composite or Total Weighted Scores 

2 In the "Abstract Reasoning" portion of the booklet, th

which of a series of choices (figures) properly carrie

logical development exhibited by a sequence of figure

Sequence" the subject must indicate which of a series 

carries out a principle of logical development exhibi

letters. 

A highly speeded test consisting of two parts of 30 .it

part, the subject is presented a flight data display 

and must determine whether certain changes in altitude 

without violating a specified time-separation rule. 

Sum of the weighted raw scores for each of the five e

(i.e., six subtests). 
qualification standards (i.e., qualifications with respect to 

aviation-related experience and/or education). Several thousand such 

applicants were operationally examined with the battery during the following 

l8 months and, although about half of them established training eligibility 

by achieving raw composite scores of l90 or higher (i.e., percentile scores 

of 70 or better), very few were selected (24). Candidates qualifying on the 

basis of previous ATC work and other aviation experience generally attained 

higher overall esc eligibility ratings than those screened with the battery. 

Moreover, training quotas continued to decline and were usually met by 

selecting candidates having CSC percentile ratings no lower than 90. To 

attain a percentile rating of 90, an applicant having insufficient 

ATC-related experience to qualify for any credit points was required to 

achieve an exceptionally high aptitude test score of 257. Aptitude-screened 

applicants were, therefore, seldom able to effectively compete for the 

available training positions. In fact, most of the relatively few 

aptitude-screened candidates selected for training prior to January 1964 

possessed at least some ATC-related experience that, although insufficient 

for exemption of the test screening requirement, warranted credit points to 

supplement ratings reflecting excellent levels of performance on the test 

battery. 

Academy training performance records for the last of the 893 candidates 

examined with the CSC test battery for research purposes only were not 

available until October 1963. By that time, Cobb and Trites had completed 

several sets of analyses of Academy performance (see Figure 2) and had 

collected post-Academy information on training progress, experimental 

ratings of job performance, and other data for several hundred of the 

examinees who had successfully completed their basic training course some 12 

to t8 months earlier. 

A series of validation analyses completed shortly thereafter yielded 

findings of timely interest to officials seeking to improve ATCS selection 

(24). Perhaps the most important of the analyses was that which, in support 

of the preliminary f indings obtained in the August 1961-May 1962 analyses, 

revealed that about two-thirds of the 271 Academy attritions among the 893 

experimentally examined trainees scored no higher than 189 on the esc 

battery, whereas two-thirds of the 622 graduates scored 190 or higher. In 

another analysis based on the entire sample, statistically significant (p § 

.OS) correlations were obtained between the aptitude test variable and most 

of the Academy training-performance measures (i.e., grades). However, when 

dealing with data on the Academy graduates only, the aptitude-test scores 

(particularly those above 210) proved very unreliable for prediction either 

of Academy training performance or of promotions, ratings of job 

performance, and/or attrition-retention status during the first 12 to t8 

months of facility training. Yet, the latter findings were of the general 

statistical type expected, because the deletion of data for the Academy 

attritions, the majority of whom were low-aptitude trainees, resulted in an 

attenuated distribution of test scores (24). 

6 
SCORE RANGE 

RAW esc 

PASS MARG~NAL 

WA 

FAIL 

-

N 

~224.0 ~80.0 170 

190.0-223.9 70.0-79.9 252 

Sl89.9 <70.0 369 

791 

Figure 2. ~ercentages by three composite score ranges of 

passing, marginal, and failing trainees who took 

the CSC ATC Aptitude Screening Test experimentally 

during l960-63: N=79l En Route, Terminal, and FSS 

trainees combined (from Trites and Cobb, 1964, 

ref. SO). 

These results prompted a rev1s1on in the selection standards. 

Beginning in January t964, the CSC battery was incorporated in the screening 

of all applicants regardless of their pre-FAA experience. Aside from other 

factors, eligibility required a composite esc score of at least 210. 

Retention of a screening score of 190 was considered, but 2t0 was eventually 

adopted because it was contemplated by FAA officials that a further 

reduction in the number of ATCS trainee positions would be necessary pending 

an increase in congressional appropriations (24). 

Revised Aptitude-Screening ~rocedures. Although the screening program 

instituted in January t964 required that all applicants for ATCS training be 

examined with the esc battery, they were screened in terms of three 

different aptitude-test-performance qualification standards (24). In 

accordance with procedures prescribed for each specific training option and 

entry pay grade being applied for, an individual's preemployment experience 

and/or level of education determined which of three tables was to be used in 

converting the applicant's composite raw score on the test battery to a 

percentile score. A percentile score of 70, considered a mandatory 

eligibility requirement, corresponded to a raw score of 2t0 on one 

conversion table, 225 on another, and 240 on the third. For example, 

candidacy for Tower or Center training at the GS-6 (General Schedule rating, 

i.e., pay grade) entry level required that ATC-rated applicants (usually 

former military controllers) score at least 2t0 on the battery, whereas 225 

was considered minimally qualifying for instrument-rated, aircraft-pilot 

7 
personnel or applicants having navigator or air-dispatcher certificates, and 

240 served as the screening standard for those having low-to-moderate 

amounts of aviation-related experience or a 4-year college degree, or 

certain diverse experiential and educational backgrounds. Moreover, the 

procedures stipulated that each applicant's percentile score, if 70 or 

higher, be supplemented with credit points awarded for those types of 

experience that had warranted use of either of the two lower test-score 

screening standards to derive the individual's overall eligibility rating 

(24). Inasmuch as the majority of the applicants possessed aviation 

experience of some sort, the dual consideration of that experience in the 

qualification process enabled them to establish training candidacy in far 

greater numbers, and generally with higher eligibility ratings, than those 

with nonaviation backgrounds. 

The relatively high aptitude-test-score screening standards of 2l0, 

225, and 240 for each of the training options remained in effect from 

January l964 until August l968, resulting in the screenout of more than half 

the applicants. However, no shortage of qualified candidates developed. 

Due to continuing budgetary limitations, training quotas remained unusually 

low throughout the entire 56-month period and consequently nearly all ATCS 

trainees were selected from among candidates having very high eligibility 

ratings--reflecting exceptional qualifications with respect to aptitudes, 

experience, and/or education. 

Eligibility for ATCS training within the F~~ has always been restricted 

to those applicants who, after having met other qualification requirements, 

satisfactorily pass a rigid medical examination. However, the procedures 

relating to medical certification of ATCS personnel were amended in l966 to 

include consideration of personality attributes (22). Since that time, 

Cattell'~ Sixteen Personality Factor (l6 PF) Questionnaire (9) has been used 

in the screening of all applicants. Physiologically qualified individuals 

for whom the l6 PF Questionnaire results indicate no significant emotional 

or mental problems are granted medical certification. Others, who usually 

represent but a small minority of the applicants, must submit to a 

psychiatric examination, the results of which may constitute grounds for 

ineligibility. 

In August of l958, a program for rapid expansion of the National 

Airspace System was initiated and a revised set of trainee-selection 

standards was adopted. In many respects, the new selection program was 

highly similar to that of the preceding 56 months. However, two new 

screening standards were implemented as a means of insuring an adequate 

supply of candidates (24). First, according to one of the new standards, 

applicants having highly specialized ATC experience (particularly in radar 

control) could be granted waivers of the aptitude-screening requirement and 

could also be appointed to training at pay grade GS-9 or higher rather than 

the normally prescribed entry grade GS-7 or lower. It was reasoned that 

such personnel would be able to complete developmental training more rapidly 

than others and thereby more quickly alleviate the shortage of 

full-performance-level controllers. Second, a score of 2l0 on the CSC test 

8 
battery was adopted as a common screening standard for most other 

applicants. The screening standard of 2l0 applied to (i) former military 

controllers unable to qualify under the "specialized experience" standard, 

(ii) pilots, navigators, air dispatchers, and others who would have 

confronted a test-score screening hurdle of 225 if they had applied in 

earlier years, (iii) 4-year college graduates with records of superior 

academic achievement, and (iv) applicants having master's degrees. A test 

score of 240 was prescribed for use in the screening of few applicants 

except those devoid of aviation-related experience, most of whom were 

college graduates with no evidence of superior academic achievement (24). 

The "specialized experience" standard remained in effect until April l972. 

Throughout that time, however, less than one-fourth of the ATCS selectees 

entered as GS-9's or higher with waivers of the aptitude-screening 

requirement (22). 

Only 7l0 (l8.9 percent) of 3,75l trainees who arrived at the FAA 

Academy during November l968 and the ensuing l7 months for basic ATCS 

training claimed to have entered the FAA as GS-9's or higher on the basis of 

hi5hly specialized ATC experience (l8). Some 446 of the 7l0 enrolled in the 

Academy's basic En Route course, while 264 entered the Terminal course. A 

study revealed that l6 percent of the 446 En Route trainees of GS-9 level 

and higher failed to successfully complete the En ~oute course and that the 

attrition rate of the 2,526 who enrolled in the same training course as 

GS-7's or lower was only slightly higher (i.e., l8.2 percent). Only l4 

percent of the 264 Terminal trainees recruited with disregard of the 

aptitude-screening requirement failed the Terminal course, whereas a 

significantly higher (p < .Ol) elimination rate of 2l.9 percent was obtained 

for the remaining 5l5 Terminal students (22). However, a later C&~T study 

(l9) by Cobb, Mathews, and Nelson (in which December l, 197l, served as a 

common date for determination of the attrition-retention status of every 

student who successfully completed either En Route or Terminal basic 

training at the Academy during l969) indicated that the trainees selected 

under the "specialized experience" standard had slightly higher post-Academy 

attrition rates than those appointed to training with pay grades of GS-7 and 

lower. The difference between the post-Academy (i.e., facility-training) 

elimination rates of the two differentially selected Terminal subgroups was 

somewhat greater than that obtained between the En Route subsamples, but 

neither difference was statistically significant. Had the results not been 

confounded by aging effects, Cobb and his associates would have concluded 

that specialized ATC experience was of little or no value to most trainees 

after Academy graduation. However, almost 23 percent of the hig~er graded 

trainees of the combined En Route and Terminal options were 35 years of age 

or older, whereas slightly less than 14 percent of those appointed as GS-7's 

or lower were older than 34 (22). 

Unpublished research by Cobb, involving several hundred ATCSs who had 

successfully completed either En Route or Terminal basic training at the 

Academy in 1969, revealed highly significant differences between the 

post-Academy attrition rates (as determined on December l, 197l) for 

trainees aged "35 and older" vs. those "34 and younger." For Academy 

9 
graduates of GS-9 level and higher, the facility-training attrition rates 

were 42 percent and t7.5 percent for the older and younger subgroups, 

respectively (22). About 25 percent of the ATCSs of GS-7 level and lower 

who were over 35 years old were attrited after returning to their home 

facilities, whereas the post-Academy elimination rate of the younger ATCSs 

having similar pay grades was only 18 percent. Moreover, several earlier 

studies (15,20,47,50) had consistently shown chronological age to be 

inversely related (at highly significant levels) to scores on numerous 

aptitude tests, various indices of Academy training progress, and ratings of 

journeyman-level job performance. 

As early as 1965, it was the view of some FAA officials that a special 

early-retirement program was needed for controllers and that the recruitment 

of ATCS trainees should be restricted to those qualified applicants who were 

relatively young (22). However, such proposed policies ran counter to the 

CSC regulations pertaining to all Federal service employees except those 

specifically exempted by congressional legislation. ~esearch concerning 

age-related effects upon ATCS performance was intensified and, in 1972, the 

cumulative body of findings prompted congressional legislation authorizing 

the FAA and CSC to further develop and implement a proposed ATCS 

"Second-Career Program." The congressional bill, Public Law 92-297, became 

operationally effective on August 14, 1972. Since that time, ATCSs receive 

credit for t.4 years of Federal service for each year of active control 

work; the normally prescribed minimum-age requirement of 55 does not apply 

to control personnel; early retirement is not mandatory but retention as an 

ATCS requires maintenance of job proficiency, and ATCSs are also offered 

training for other jobs (i.e., "Second-Career Training"). Moreover, as a 

means of countering aging and "burnout" effects, the FAA was permitted to 

establish a screening standard with respect to age. 

Programs Designed to Aid Minorities and Women in ATCS Selection and 

Training. During the 1960~ Government-wide awareness-of the social need 

to provide opportunities for certain economically and culturally 

disadvantaged groups prompted the FAA to implement a new source of 

recruiting for the ATCS occupation. 

The new project was originally proposed in an FAA Organizational Bias 

Seminar, and was committed by the Administrator to the Secretary of 

Transportation in 1968. It was termed the "t50 Program." The purpose was to 

provide for entry into the ATCS occupation at the GS-~ level rather than the 

previous GS-5 minimum accession level. The Predevelopmental program was 

designed primarily for persons of underprivileged backgrounds, and as a 

means of hiring more minorities in ATCS positions, which constitute about 

half of all FAA positions. 

The program involved a training agreement with the CSC, whereby a 

number of positions were allotted on a 6-month recycling basis. Special 

6-month qualifications training was given at the FAA Academy upon the 

trainee's entrance on duty. The courses were designed to provide the fully 

qualified GS-4 ATCS with a general background of aviation knowledge prior to 

entering the Academy. 

10 
On October l, l969, the CSC approved training agreements covering ATCSs 

for a 2-year duration. This allowed for accelerated promotion from the GS-4 

entrance level to GS-5 after completion of 6 months of Academy training 

(30) 0 

Since inception of the "lSO Program," evaluation has tal<.en place in 

several ways. The first 2t ATCS trainees who entered the Academy on 

February 9, 1970, were compared by the FAA Office of Personnel in 

biographical background with proposed course content, and based on this 

comparison course refinements were introduced. Those classes were graduated 

in July t970. End-of-course critiques completed by trainees and instructors 

were evaluated, and further critiques were mailed and completed at field 

installations where graduates were subsequently assigned in February t97t. 

Several refinements in the program were made as a result of the initial 

evaluation process (29). 

In early t97t the FAA Office of Personnel conducted an informal 

evaluation that was based primarily on discussions with students, faculty 

members, and regional personnel staff, Refinements were made in recruiting 

efforts as a result of this ,study. In September l 97t a more formal 

evaluation of the "lSO Program" was performed by the Office of Personnel 

(29). T~e general conclusion of the study was that the program "provided an 

additional rung in the ladder" for a high percentage of minorities who 

otherwise would not have become agency employees. A later study (t973) by 

the same office verified this general conclusion (30). 

Boone (~) performed a path analytic study of the "t50 Program" to 

determine if the program indeed had a direct impact on the trainee's ability 

to achieve success in Academy training. The two previous informal studies 

cited above (t97t and t973) had shown that the "tSO Program" resulted in a 

higher percentage of women and minorities in ATC work; however, no explicit 

evaluation had been performed to demonstrate that the increase in the number 

of women and minorities performing ATC work resulted from the instruction 

received in the program rather than from a mere increase in the number of 

women and minorities recruited and hired because of the "tSO Program." The 

participants in the study consisted of all persons who came through the 

Predevelopmental program during calendar years t974 through 1976. The 

effect of the program on Academy success was reviewed for nonminority men 

and women and for minority men (there were too few minority women to form a 

basis for analysis). The general conclusion of the study was that the 

Predevelopmental program overall aided the disadvantaged to achieve success 

in the FAA Academy. The general effect, however, was not true for the 

subgroups. The path models indicated that nonminority men and women 

(especially women) were aided by the program; however, minority men 

(predominantly Blacks) were not (4). The study suggested that recruitment 

and selection testing procedures could have produced this differential 

effect. A further study of attrition in Predevelopmental recruits was 

recommended. 

11 
Current Status of Selection Standards. The ATCS selection procedures 

remained essentially-unchanged from August 195g until April 1973. At that 

time, selection at the GS-9 level on the basis of ''specialized experience" 

ceased (April 2, 1973). Simultaneous with the reinstatement of mandatory 

aptitude-screening procedures for all applicants, the selection procedure 

that automatically precluded the eligibility of any applicant more than 30 

years old was implemented (24). With the exception of the two aspects just 

mentioned, the 1973 selection progr~m was highly similar to that of 1968. 

Also, none of the current (1979) screening standards differ significantly 

from those of 1973. Nonetheless, recruiting demands have so drastically 

declined since t968 that a current-day candidate has virtually no chance of 

being appointed to training unless his or her overall eligibility rating far 

exceeds that which would have warranted selection during the 1968-72 period. 

In addition, the Academy training program was modified in 1976 to include 

new pass/fail criteria based on a curriculum that assumed zero ATC knowledge 

on the part of the new trainees. CAMI was assigned the task of maintaining 

the longitudinal data base for all trainees beginning in 1976. That 

computerized base includes CSC (now OPM) selection test scores, biographical 

information, all Academy training scores, and subsequent field performance 

data from Academy graduates. 

CAMI is also active in current efforts to update and improve ATC~ 

selection procedures. These efforts are partly rooted in recommendations by 

a task force which was commissioned by the FAA in December 1974 to review 

the agency'? selection policies. The task force, in a 1975 report (26), 

identified the following areas for further consideration: (i) the testing 

and screening of applicants for ATC work, (ii) the CSC rating guide used to 

grant additional points for certain types of related prior experience, and 

(iii) the evaluation of further recruitment and testing practices for 

cultural bias against women and racial minorities. As a result of that 

review, two major studies were performed with the goal of further improving 

ATCS selection through revised aptitude testing. 

The first of these two studies, by Education and Public Affairs (EPA), 

a private company, was contracted by FAA (26,27,36) to determine the 

potential of an experimental test battery to predict ATCS success. An 

aggregate "success" criterion was used in the study, based on a composite of 

supervisory assessment and career progression. The experimental tests 

considered were the present ATC selection battery, an ATC General 

Information Test, ATC Occupational Knowledge Test, Multiplex Controller 

Aptitude Test, Directional Headings Test, Dial ~eading Test, and an 

Arithmetic Reasoning Test. The EPA study (36) provided data-based 

predictions but was not able to demonstrate the relative value of the 

experimental tests vis-a-vis the present battery, since no information was 

available to EPA on the experimental tests from the total applicant group. 

To evaluate the relative value of the tests that demonstrated potential 

in the EPA study, the CSC in 1977 administered two of the experimental 

instruments, the Multiplex Controller Aptitude Test (MCAT) and the 

Directional Headings Test (DHT), to approximately 7,000 ATCS applicants in 

12 
conjunction with the regular CSC ATC test battery. These data were to be 

used along with the analyses performed in the second major study which was 

conducted at CAMI by Boone and Lewis (5,6,7). The purpose of the CAM1 

effort was to determine which of the selected experimental tests, either 

independently or in combination with present esc tests, were the best 

predictors of success at the FAA Academy. CAMI data came from trainees 

selected for ~TCS work beginning May 1976 through April 1978. During their 

first day at the Academy, new trainees were tested by Boone and Lewis with 

experimental test batteries whic~ included a Biographical Questionnaire, a 

Dial Reading Test (DRT), the MCAT, and the DHT. Only ATCSs who had a 

complete data set were included in the final sample of 1,828 trainees. 

The DRT used in the C~I study is Part I from the u.s. Air Force's 

Dial and Table Reading Test (32)~ the examinee is presented with seven. 

dials for each set of six questions and is required to read the correct 

value on the correct dial in order to select the correct answer from among 

five given alternatives. The MCAT (28) presents pictures of simulated air 

traffic crossing a controller's display, and a table of altitudes, speeds, 

routes, and identifiers. The test is speeded to reflect changes in aircraft 

position with successive items. A primary task is to predict violations of 

aircraft separation standards. Other questions measure aptitudes such as table 

reading, spatial visualization, and arithmetic reasoning. Items alternate from 

one type to another with increasing levels of difficulty. The DHT (19) is a 

highly speeded test with items that present the examinee with one, two, or 

three pieces of information reflecting the cardinal points on a mariner's 

compass. In Part I of the test the examinee must determine very swiftly if the 

information conflicts or agrees. Each item is followed by five response 

categories: "North?," "East?," "West?," "South?," and "Conflict?," and the 

examinee must mark one of the response spaces under the correct category. Part 

II is similar except the examinee must mark the response space for the exact 

opposite of the heading in the item . . 

Scores on the DRT, MCAT, and DHT and on the tests composing the present 

CSC battery were correlated by Boone (5) with the averaged laboratory scores 

from Academy training. These correlations were then employed in an 

iterative stepwise regression (stepdown procedure). The tests that made a 

significant contribution in predicting Academy scores were then used to form 

a composite, and the multiple corre-lation was computed for the old test 

battery and the new test battery. Six regression ~odels were explored~ two 

of them demonstrated a statistically significant increase in the multiple 

correlation over the old test battery (5). Of the two models, one involved 

use of the MCAT with two current CSC tests (CSC 24, Computations; CSC 157, 

Abstract Reasoning), the other involved no current CSC tests but included 

the MCAT, DHT, and DRT. A report of the statistical findings was prepared 

in 1979 for OPM and FAA consideration (5). Final action on a new aptitude 

selection battery is currently pending. 

Summary. Active research at CAMI on the problem of ATCS selection was 

undertaken soon after the establishment of the Institute in 1960. Under the 

13 

' 
direction of Trites and Cobb, followup research immediately began on the 

predictive validity of the composite of aptitude tests originally studied by 

Brokaw. After further exploratory research on a varietv of aptitude 

measures, the validity of several such measures for predicting success in 

training was fairly well established. Further research at CM1I with CSC 

tests of similar content led the esc for the first time to establish 

selection tests for screening ATCS trainees in July 1962. Continued 

validation research prompted a revision of esc selection standards in 

January 1964, with all applicants being required to ta~e the selection 

battery. However, prior experience and education continued to be the 

primary determinants of the selection decision. The high standards (and 

concomitant low selection rates) established in 1964 were revised in 1968 

due to an expansion of agency hiring. During the period from 1962 through 

1972, in addition to continuing validation research on the changing esc 

criteria, Cobb and his associates at CM1I investigated a number of factors 

relevant to selection and screening of ATCSs. Those factors, which are 

discussed in more detail below, included research on attrition, age, prior 

experience, education, sex, and military ATC training. The CM1I research on 

age led directly to the establishment of the age 30 screening standard in 

1973. At that same time, mandatory aptitude screening was reinstated (those 

with prior radar experience had been exempted in 1968). Since that time the 

selection standards have remained essentially the same. During the latter 

half of the 1970's, C~~I research focused on evaluation of the impact of the 

special entry "150 ~rogram" for disadvantaged persons which was implemented 

in 1969, on studies of optimal combinations of old and new aptitude 

screening measures to form a potential new aptitude screening battery, on 

studies relevant to the Uniform Guidelines on Employee Selection (discussed 

below), on developing field performance ratings, and on the computerized, 

longitudinal ATCS data base for continuing validation research. 

Some Followup Studies on Attrition 

It had been ascertained in CAMI's primary validation study with the 893 

pre-t964 ATCS trainees that Academy-basic-training attrition rates were: 

(i) 30.3 percent for the total group, (ii) only 16.4 percent for the 1t7 who 

attained composite raw scores of 210 and higher on the CSC test battery, and 

(iii) 38 percent for the group of 576 having scores of 209 and lower (see 

Figure 3). Thus, it had been anticipated that adoption of the CSC battery 

for screening purposes could result in a reduction of the attrition rate at 

the Academy from approximately 30 to about 16 percent. A reduction did 

occur but not to the extent expected (t9). For example, 22 percent of the 

2,822 men who presumably met or exceeded the aptitude screening requirement 

and who entered the Academy during November t968 through March 1970 failed 

to successfully complete their training course. While the attrition rate of 

22 percent was significantly lower than the 30.3 percent obtained for the 

total validation sample of 893 trainees, it was somewhat above the failure 

rate found for the 3t7 who had aptitude scores greater than 209. The 

disparity between the attrition rate predicted in 1964 and the rate obtained 

14 

' 
Sample on which the CSC 

ATC Test Battery was 

originally validated. 

N=893 Enroute & Terminal 

Trainees of 1961-1963. 

CSC Score: 129 130 

& < -149 

N Pass: 13 33 

N Fail: 38 46 

N Total: 51 79 

150 

-169 

52 

47 

99 

Academy 

Training 

Failures 

19.6% 19.3% 

170 190 

-189 -209 

124 135 

51 37 

175 172 

16.9% 

210 

-229 

126 

25 

151 

D Academy 

Training 

Passes 

6.3% 

230 250 

-249 & > 

87 52 

23 4 

llO 56 

Figure 3. Distributions of CSC ATC Aptitude Screening Test 

scores for the 893 experimentally examined 

entrants into Academy ATCS training during t96t-63 

and for the 28t operationally examined trainees 

who entered during t970 (from Cobb and Mathews, 

t972, ref. t9). 

N 

Total 

622 

271 

893 

in t970 prompted Cobb and Mathews (t9) to examine possible reasons for the 

obtained rate. 

Two assumptions were made (t9). First, an aptitude screening battery 

predicated on such a vast and diverse amount of research as had been 

accomplished by CAMI would have been expected to maintain considerable 

effectiveness over time as an initial screening device. Second, inasmuch as 

the esc adheres to rigid control and accountability procedures, there was 

little likelihood that the aptitude measuring devices would have been 

subjected to compromise. 

The most likely reason selected by Cobb and Mathews (t9) for the 

disparity between the predicted and the obtained attrition rates was the 

impact of FAA ATCS selection practices on the data used to determine 

validity of the selection test battery--data based on such highly screened 

personnel were apt to be grossly attenua~ In addition to the medical, 

experimental, aptitudinal, and educational screening qualifications of ATCS 

applicants, several unpublished CM.1I studies indicated that ATCS trainees 

were also well above average in intelligence (l9). One investigation, which 

15 
preceded adoption of the esc battery for operational purposes, was 

summarized by Cobb and Mathews (t9) as yielding a correlation of .8t between 

the summary esc aptitude scores of several hundred trainees and their 

so-called IQs (intelligence quotients) derived from performance measures on 

the CTMM. The aptitude scores for the group averaged t93 and the mean IQ 

was ltO.S. Although the study indicated that the CSC scores were more 

useful than the latter for prediction of training outcomes, the relationship 

between the two variables provided the basis for development of a regression 

equation which subsequently permitted estimation of the general intelligence 

level of operationally examined recruits relative to that of t~e general 

population. For example, it has been determined that a minimally qualifying 

score (of 2l0) on the CSC battery approximates a CTMM IQ of l20, which, 

according to the CTMM Manual (45), corresponds to the 88th percentile for a 

"normal" (or ·general) population and about the 70th percentile for college 

freshmen (t9). Thus, these trainees also represented a bright group of 

people. 

Several analyses by Cobb, all of which involved relatively small groups 

of trainees recruited between l968 and t970, produced (predictably) 

relatively low correlations between the global scores on the esc battery and 

summary measures of training performance. Specifically, the validity 

coefficients ranged as low as .04 and no higher than .26 for prediction of 

the pass/fail training criterion and from .03 to .39 for training grade 

averages (t9). These and other similar findings, however, were expected on 

the basis of restriction of range and other factors noted below. 

If it were assumed that ATC training performance evaluation standards 

remained unchanged from t963 to t970, a failure rate of somewhat less than 

22 percent would have been anticipated for the later trainees. While little 

or no evidence was available to conclusively prove or disprove equivalency 

of the performance criteria, the issue was one frequently confronted in 

research aimed at progressive improvement of personnel selection procedures. 

It is commonly referred to as "the problem of creeping criteria," and, 

inasmuch as officials responsible for training traditionally strive to 

upgrade their programs, it is a problem that is normally and hopefully 

anticipated. 

Cobb and Mathews (t9) hypothesized that ATC training programs and 

performance evaluation standards had been upgraded~ that the changes (the 

exact nature and extent of which would have been difficult to determine 

reliably) were partially attributable to training requirements associated 

with the increasing complexity of the air traffic management system and in 

part to the inherent tendency of training personnel to ''customize" 

instructional material, instruction, and/or subjective performance 

evaluation standards relative to the general level and range of mental 

abilities represented in the incoming classes. Moreover, the vast majority 

of trainees recruited since t963 were of high mental caliber and, thereby, 

comprised groups which would be characterized by substantial restriction of 

range of aptitudes (19). 

16 
Cobb, Mathews, and Nelson (21) took a detailed look at the various ways 

in which the characteristics of the ATCS trainees and their attrition rates 

differed between 1960-63 and 1968-70. This study involved comparisons of 

Academy basic training elimination rates and post-Academy attrition and 

retention rates of personnel who were recruited during each of the two 

widely separated time periods for each of three different types of ATCS 

training. Data were obtained for a total of 6,367 former trainees. Exactly 

2,000 of the 6,367 had entered the Academy during September 1960 through 

August t963, before the CSC battery became operational in the screening of 

most applicants. The 2,000 included 733 entrants into Terminal training, 

t,008 En Route trainees, and 259 FSS personnel. The remaining 4,367 

trainees, the vast majority of whom were required to qualify on the esc 

test, had entered the Academy during October t968 through March 1970; of 

the 4,367, 935 were Terminal trainees, 3,t59 were En Route personnel, and 

273 were FSS personnel. 

Percentages reflecting the Academy elimination rates for the earlier 

versus the later time periods, respectively, were: 20.9 and t9.3 for the 

Terminal personnel, 32.0 and t7.9 for the En Route trainees (this difference 

was statistically significant, p < .01), and 18.5 and t2.8 for the FSS 

personnel. The mean Academy elimination rate of 26.2 percent for the 2,000 

total pre-1964 trainees was significantly higher (p < .Ot) than the 

17.0-percent rate obtained for the 4,367 recruits of the more recent time 

period (2t). Moreover, the 17.9-percent rate was only slightly higher t~an 

a rate of 16.4 percent that Cobb had projected on the basis of results 

obtained in an earlier study of the 893 pre-t964 trainees experimentally 

examined with the esc battery (before it was adopted for operational use). 

Followup procedures were employed whereby those Academy graduates who 

were still in ATC work on December 1, 1971, were designated as "retentions" 

while those eliminated after completion of Academy training were designated 

as "post-Academy attritions." The post-Academy attrition rates for the 

Terminal, En Route, and FSS entrants of 1960-63 were 16.0, 22.8, and 18.t 

percent, respectively, whereas the corresponding rates for the recruits of 

t968-70 were 10.t, 20.3, and 5.9 percent (21). The En Route option was the 

only one for for which the difference between the rates was not 

statistically significant. 

Analyses pertaining to subgroups, each composed of one to four former 

incoming classes of the Academy's Terminal, En Route, or FSS training 

courses, yielded significant inverse relationships between the Academy 

elimination rates and post-Academy attrition rates of the trainees (see 

Figure 4). Such findings were remarkably consistent for personnel who 

entered each type of training during either of .the two time periods. These 

findings also suggested the possibility that the basic training courses 

could have been utilized more effectively in precluding the advancement of 

many recruits to facility training from which they were eventually 

eliminated (21). 

An investigative phase pertaining to 645 of the Academy Terminal 

graduates and 2,162 En Route basic training course graduates of January 1969 

17 
1-' 

00 

90• 

80 

70 • 

Percent 60 

of ATCS 

Trainee SO• Group• 

(All OptiaD•) 40 • 

30 

20. 

10 

... 

-- + '-...... 

+ ---· ............. ... __ ... ......._ 

IC: ---X 

--- + 

+ - Retentia

0 Academ, 

:X ....... ----

................. 

S: -:,7,T i ----- --- 0 0 

X--- X ---X--- 

0 

0 Post-Aca

-----

0 ...... """ 

Oct Nov-Dec Jan-Feb Mar-Apr May-Jun Jul-Aug Sep-Oct Nov-Dec Jan

1968 1968 1969 1969 1969 1969 1969 1969 1

ietentiaD• (Dec:. '71) • 

N 120 326 102 200 538 356 166 208 5

_ !'_e!:.c!Lnl_ af_GI,Pyp __ _ l9.a.5 _ _ _ 7!f..§. __ §.5.a.4 ___ 6!.!! __ §!J.a.e ___ 6J..1 __ 2h6 ___ 6!.g, __ 

Post-Academy Attritions 

N Ca•e• 29 107 42 54 171 78 45 52 

_ __ !9.a.2 __ _ 2!f..2_ __ l6.a.9 ___ __ !9.a.l ___ lfi • .Q __ !5.a.6 ___ 12_.1, __ 

Ac:ad.., AttritiaD• 

N Ca•e• 2 4 12 34 187 125 77 81 

_ ___ l.a,3 ___ g,.,! ___ 7.a,7 ___ __ l,O.a,9 ___ 21_.,i __ 1_6.a,7 ___ 21.§. __ 

Total K of Group 151 437 156 288 896 559 288 341 

Figure 4. Percentages of entrants into the Academy's En Route, Terminal

courses during October 1968 through March 1970 who were Academ

attritions, facility-training attritions, or were still in FAA 

December 1976 (from Cobb, Mathews, and Nelson, 1972, ref. 21
through March l970 revealed that the post-Academy retention rate of the 

Terminal trainees was 87.8 percent and that the En ~oute retention rate was 

signficantly lower at 75.7 percent (2l). A series of analyses in which no 

distinction was made with respect to the trainees' pay grades or 

entry-into-training qualifications indicated that the retention rates varied 

appreciably from facility to facility. However, the retention rates did not 

appear to be related, positively or negatively, to the traffic-density 

levels of the facilities. For example, the mean retention rate of assignees 

to the l2 Level-IV (or top-ranked) Terminal facilities was 89.2 percent, 

whereas the retention rates of trainees averaged 87.9 at all Level-l and 

Level-II facilities while the mean was 87.0 percent at the Level-III 

installations. Although significantly low~r than those obtained for 

Terminal personnel, the mean retention rates of En Route personnel at the t3 

Level-II Centers (75.4 percent) and t4 lower ranked Centers (75.8 percent) 

were highly comparable (2t). 

The study also revealed that personnel who qualified for entry into 

training at the GS-9 level and higher on the basis of pre-FA~ specialized 

experience had significantly higher ~cademy graduation rates than the 

conventionally recruited trainees. However, the post-Academy attrition 

rates of the higher rated trainees averaged about twice that of the less 

experienced trainees at the Level-IV and Level-III Terminal facilities; 

also, their mean attrition rate at the t3 top-ranked Centers was higher, 

though not significantly so, than that of other trainees. It was only at 

the Level-l Centers and Terminal facilities of the two lowest levels that 

t~e mean attrition rates (or mean retention rates) reflected favorably on 

these more experienced trainees--and by only one percentage point (2t). 

Although other types of occupations that make use of one or more sets 

of initial screening tests as well as formal centralized training are not 

directly comparable to air traffic control work (nor to each other), their 

attrition rates were examined to provide at least some perspective from 

which ATC Academy attritions of l968-70 might be viewed (2t). For example, 

published reports available at that time (circa t970) about several 

occupational groups that were carefully prescreened prior to 

entry-into-training revealed training-attrition rates ranging from 22 to 43 

percent. Included among these were attrition rates of 35.6 percent during 

United States training of Peace Corps volunteers (3t); 22 percent of 

nursing students in their first year of training (33) (a different study 

(44) of nursing turnover in a teaching hospital showed that 38 percent of 

the nurses stayed on the job less than t year); 43 percent of Army officer 

candidates during 23 weeks of training (~2); and 35 percent of a sample of 

naval aviation students (excluding those who failed to complete training due 

to medical or disciplinary problems) who, in addition to prescreening, were 

typically recent college graduates (2). 

Since ATCSs make up about half of the FAA work force, some comparisons 

of their annual attrit.ion rates with rates of non-ATCS personnel provided 

another occupational perspective. The same caveat noted above with regard 

to comparing different types of occupations (as well as different GS-grade 

19 
levels and other characteristics), of course, applies to t~ese comparisons. 

However, based on FAA personnel records, Cobb, Mathews, and Nelson (2l) 

calculated the average attrition rate for all FAA employees not in the air 

traffic control occupational specialty to have been approximately t3.5, 9.3, 

and 9.l percent for calendar years t969, t970, and l97l, respectively 

(averaging l0.6 percent for the 3 years). The rates during the same time 

periods for all ATCSs were 5.7, 7.8, ana 5.0 percent (averaging 6.3 

percent). If the assumption is made that those who were attrited from the 

FAA Academy would have been later ATCS attritions anyway, then, following 

selection and Academy screening, the attrition r a tes of ATCSs would have 

dropped to approximately 3.3, 5.6, and ~.9 percent, respectively, for the 

t969 through t97l periods (a 3-year attrition rate averaging ~.6 percent). 

These 3-year attrition rates were also examined by means of 

longitudinal comparisons between ATCSs and noncontroller FAA personnel (2t). 

Data were made available by FAA's Office of Manpower regarding all full-time 

GS employees (i.e., excluding temporary or part-time help) hired during the 

6-month period from October t968 through March 1969. During that period, 

9!+9 ATCSs (including many who entered the Academy during April or later) 

were hired at the GS-5 through GS-9 levels; a total of 2t7 non-ATC 

employees were also hired at those same levels. The overall attrition rate 

(as of December t97t) for the 2t7 noncontrollers was 32.7 percent; for the 

9~9 ATCSs, the rate was 24.6 percent (including Academy failures). 

Summary. CAMI research on ATCS attrition demonstrated that the overall 

l968-70 attrition rates compared favorably with attrition rates in other 

occupations utilizing highly competitive prescreening prior to 

entry-into-training as well as in non-ATCS FAA occupations. Other ATCS 

attrition research demonstrated that: 

(i) The l964 change in CSC entry standards significantly reduced 

(ii) 

(iii) 

(iv) 

( v) 

attrition rates; 

Attrition rates were negatively related to CSC composite scores; 

"Special entry" ATCS trainees had significantly higher Academy 

graduation rates; however, they also had higher post-Academy 

attrition rates; 

Attrition rates were not related to the air traffic density 

characteristics of a facility; and 

Attrition rates at the Academy were inversely related to 

post-Academy attrition rates. 

Thus, initial selection screening and Academy training-screening 

appeared to be appropriately related to attrition rates by t970, although 

overall attrition rates remained high and were costly to the agency. 

Additional attrition research, detailed in the next section, led to revised 

esc selection standards aimed at reducing attrition. 

Age~~ Selection Factor 

Perhaps the most important of all the CAMI studies on ATCS selection 

were those demonstrating the effects of age on training and job performance. 

20 
Training records for groups of ATCS personnel recruited since l960 and a 

number of unpublished earlier CAMI studies consistently revealed a definite 

relationship between chronological age and probability of attrition. 

To enter ATCS training at the time CAMI began its research program, an 

individual had to be at least 2l years old, but there was no upper age 

limit. It had long been felt by training and supervisory personnel even in 

l960 that a marked negative relationship existed between age at entry into 

training and subsequent performance (SO). That is, the older trainees did 

not perform as well as their younger classmates either in training or 

subsequently. 

AGE 

GROUP 

45-51 

39-44 

33-38 

27-32 

21-26 

SATISFACTORY MARGINAL SEPARATED FAIL 

- -

Figure S. Percentages of ATCSs by age groups in four 

training and job performance categories: 

Satisfactory, marginal, separated, and failed 

(from Trites and Cobb, l964, ref. SO). 

TOTAL 

N 

21 

150 

15 7 

315 

567 

1210 

In CAMl's first assessment of tl-tis relationship; the data given in 

Figure S were compiled by Trites and Cobb (SO) from several different 

samples of ATCS trainees. In the figure, "Fails" are those not completing 

training, "Separated" are individuals completing training but no longer with 

the FAA, "Marginals" are individuals still with the FAA but about whom a job 

supervisor had some reservations concerning adequacy of job performance or 

21 
potential, and the "Satisfactory" individuals are those satisfactorily 

working at their ATCS specialty. The negative relationships between age at 

entry into training and job performance are obvious. The older the trainee, 

the less likely he or she was to complete training or remain with the FAA 

(50). In an unpublished 6-year followup study conducted by Cobb on 688 

trainees (who comprised the successive classes of the Academy's basic 

training courses during August t96t through March t963), it was found that 

(i) 72 percent of tlB men of age 36 and over failed their initial training 

course whereas only 33 percent of 570 younger students failed, and (ii) 

older trainees who did pass the Academy also tended to experience greater 

difficulty than their younger colleagues in subsequent phases of on-the-job 

training (l8). In a later published study that included these ATCSs and 

later trainees, entry age proved to be inversely related to both the 

aptitude-test variable and the criterion measures (t5). Some 668 (74.8 

percent) of the 893 examinees were no older than 30 and the remaining 225 

were almost equally distributed among the age brackets 3l-35, 36-~0, and 

~l-and-older. Although only l48 of the 668 youngest trainees were Academy 

attritions, 63.5 percent (N=94) of the l48 scored t89 or lower on the CSC 

test battery, compared to 35.8 percent (N=t86) of the 520 youngest 

graduates. Trainees of the successively older age brackets had 

progressively higher Academy attrition rates and lower mean scores on the 

test battery. Almost 78 percent (N=59) of the 76 trainees aged ~l and older 

(many of whom were military retirees with lengthy ATC experience) failed to 

successfully complete Academy training, and only 22 (37.3 percent) of the sq 

attained test scores of l90 or higher, including 9 with scores of 210 and 

higher (24). The consensus that older controllers generally performed their 

duties less effectively than younger ATCSs was supported by the results of 

several studies (l5,48,50), all of which indicated that performance, as 

evaluated by supervisors or peers, was apt to decline after age ~0 without 

regard to tenure or experience in ATC work (l8). 

A series of published CAMI investigations (t8,20,22,48,49,50), dating 

back to t96l, indicated that the training attrition rates of groups of 

trainees of age 3t and older were generally two to three times higher than 

those of the younger trainees (see Table 2). Other studies (t5,23,48) in 

which experimental ratings of job performance were collected on 

journeyman-level ATCSs from both their supervisors and their peers revealed 

that the mean performance ratings of controllers within every age category 

beyond 40 were significantly lower than those of the younger subgroups (see 

Figure 6). Such findings and other unpublished analyses that Cobb provided 

at the request of the FAA and the CSC played a decisive role in the FAA's 

obtaining Congressional legislation in 1972 permitting the establishment of 

an optional early retirement program for controllers and also the imposition 

of an upper age limit of 30 in the recruitment of controller trainees (24). 

(Note: The maximum age limit of 30 does not apply to FSS personnel nor does 

the early retirement program.) 

Summary. Implementation of the standard that precludes the training 

eligibility of any applicant older than 30 has been viewed by many within 

the FAA as representing the most significant step ever taken to improve the 

22 
Table 2. Compar.i son of Attrition (Attn) and Retention (Ret) Rates by CSC ATC Aptitude Sc

Level, Type of Rated Pre-FAA Experience, and nichotomized Age Grouping for 2,349 

En Route and Terminal ATCSs Who Entered the Academy (Acad) During 1969. 

P-A Refers to Post-Academl Attrition {from Cobb & Nelson 1 1974 1 ref. 22). 

CSC ATC Aptitude Test Score 

Unknown 209 & Lower 210 & Hf<]her 

Acad P-A Ret Acad P-A Ret Acad P-A Ret 

Pre-FAA Attr Attr Jan Attr Attr Jan Attr Attr Jan 

Expertence N Rate Rate 1973 N Rate Rate 1973 N Rate Rate 1973 

Age Categorl Tot % % % Tot % % % Tot % % % 

N 

w Non-ATC Pilot 71 57.7 21.1 21.1 1 100.0 0.0 0.0 115 27.8 33.0 39.1 

31 ATC & Pilot 16 25.0 18.8 56.3 3 33.3 66.7 o.o 9 0.0 22.2 77 .a 

&. Non-Pilot ATC 125 35.2 26.4 38.4 40 27.5 25.0 47.5 48 10.4 25.0 64.6 

older Other 84 64.3 10.7 25.0 5 60.0 20.0 20.0 148 27.0 26.4 46.6 

Total 296 48.3 20.3 31.4 49 32.7 26.5 40.8 320 24.1 28.4 47.5 

Non-ATC Pilot 97 35.1 21.7 43 . 3 0 o.o 0.0 0.0 245 9.0 20.4 70.6 

30 ATC & Pilot 29 13.8 20.7 65.5 11 0.0 0.0 100.0 24 0.0 29.2 70.8 

& Non-Pilot ATC 277 17.3 15.5 67.1 88 6.8 20.5 72.7 350 3.1 19.4 77.4 

younger Other 165 54.6 15.8 29.7 3 o.o 0.0 100.0 395 9.9 20.3 69.9 

Total 568 31.0 16.9 52.1 102 5.9 17.7 76.5 1014 7.1 20.2 72.7 
en 

0 55 

c:: 

-.. 

0 

0:: 

en 

en 

., 

c:: 

., 

> 50 

.. 

u 

., 

.... 

.... 

liJ 

en 

u 

..... 45 

<X 

Age 40 and 

.,.,o Younger 

.,o ..... .._.._o~.; 

o.._.__ /, x 

--o 

68< 

X 

Age 41 and 

Older 

7 II 8 > TOTAL 

Years of Experience 

8 9-10 

Figure 6. Means of ratings combined from supervisors and 

peers for "Older" vs. "Younger" radar ATCSs of 

different experience groups (adapted from Cobb, 

1967, ref. 15). 

selection process (24). This belief stems from consideration of findings 

obtained in a number of CAMI studies. Due to the standards prescribed for 

evaluating and weighting various types of aviation-related experience as a 

selection factor, relatively high proportions of the selectees who 

established their candidacy ratings during periods preceding imposition of 

the age limitation were more than 30 years old, including appreciable 

percentages of selectees in their 40's and some who were more than 50 (24). 

However, the followup studies of groups recruited during t960 through 197t 

always revealed significant inverse relationships between training-entry age 

and training-performance measures (t5,23). The effects of age pervaded all 

experience subgroups, indicating the need for establishment of a standard to 

preclude the qualification and selection of older applicants, regardless of 

their experience backgrounds (~2). Moreover, research (t5,21) also 

demonstrated that the job proficiency of full-performance-level ATCSs, or 

journeyman-level controllers, generally tended to decline progressively 

after age 40. Such findings retrospectively attested to the validity of the 

FAA's current policy of recruiting only relatively young personnel for ATCS 

training. 

24 
Aviation-~elated Experience as a Selection factor 

Throughout the history of the FAA and that of its predecessor 

organization, the CAA, ATCS selection programs have included standards 

predicated on the philosophy that almost any type of aviation-related 

experience should be of value for prediction of success in ATCS training and 

work. Inasmuch as previous experience in air traffic control (usually 

acquired in military service) has always been considered of paramount 

importance, standards have invariably prescribed that it be heavily 

weighted, directly or indirectly, as a selection factor. Other types of 

aviation experience traditionally regarded as important, but generally 

weighted more moderately than prior ATC work, include experience (military 

or civilian) as an aircraft pilot, a navigator, a communications expert, a 

radar surveillance specialist, and a flight dispatcher. ?rior to 

implementation of mandatory aptitude-test screening procedures in t964 (and 

exclusive of brief trial periods for procedures resulting in the selection 

of relatively few trainees), the eligibility ratings of medically qualified 

ATCS applicants were determined primarily on the basis of assessments of 

aviation-related experience and education (24). 

Briefly stated, selection programs have always been formulated to 

result in the recruitment of as many controller trainees as possible from 

applicants who, in addition to other qualifications, possessed previous ATC 

experience. The appropriateness of this policy has been repeatedly 

confirmed by the results of CAMI followup studies of personnel who entered 

ATCS training during the decade ending in t970 (24). Unfortunately, 

however, the pool of former military controllers has progressively 

diminished during the past t9 years, and the FAA has therefore recruited 

increasingly greater proportions of its ATCS trainees from candidates having 

other aviation backgrounds and also from those having no aviation experience 

of any type--but who qualified on the basis of aptitude-test measures and 

assessments of education. 

Unpublished studies in which biographical data were collected and 

analyzed for large samples of ATCSs recruited from the t960's through the 

early t970's generally showed that 40 percent or more were former military 

controllers and that 40 to 45 percent of the remaining selectees held 

aircraft-pilot ratings (22). The results of several early CAMI studies 

(t8,20,49,50) suggested that various types of pre-FAA ATC experience were 

primarily beneficial to the ATCSs during the basic-training phase only, 

whereas all other experience, including aircraft-pilot experience, appeared 

to be of questionable value at any stage of the training. Yet, little or no 

information had been gleaned through the t960's to indicate whether the 

pilot-experience standards should be abolished, drastically revised, or 

modified only slightly. 

The validities of aviation-related experience (pilot, navigator, etc.) 

and also other kinds of experience for prediction of training progress had 

never been firmly established (22). While several C&~I studies, though 

25 
focusing on other objectives, had included a comparison of the training 

attrition rates for groups of nonrated trainees and those having pre-FAA 

ratings as pilots, ATCSs, or communications specialists, an issue seldom 

dealt with was the amount of each type of experience. Moreover, the 

available results had generally been difficult to interpret due to the 

presumed (but unassessed) interaction effects of numerous variables (22). 

The trainees established their eligibility for training on the basis uf 

various factors and standards and, inasmuch as chronological age wa~ not 

considered in the screening process until t973, those with rated experience 

tended to be somewhat older than the nonrated trainees. Research 

(t7,t8,t9,20) had consistently shown age to be inversely related to 

performance on the CSC ATC test battery and to measures of training 

performance. Yet, no studies prior to t973 had been accomplished to 

determine the extent to which the aviation-related experience might vary as 

a function of the interaction effects of age and aptitude level and also 

education. 

Most of the early CAMI studies referred to above involved comparison of 

Academy-training-performance criterion measures only for trainees having 

different types of experience. In each such investigation, the trainees who 

held pre-FAA ATC ratings were found to have significantly higher 

training-course grade averages and/or graduation rates than all other 

groups, whereas the mean differences between the pilot-rated trainees and 

the communications-rated and nonrated personnel were usually rather small 

and not statistically significant (22). 

Such results, however, did not necessarily warrant the conclusion that 

pilot experience should be completely disregarded in the screening of ATCS 

applicants; the standards might be merely too liberal. Under the 

standards, a total of five points was (and still is) credited toward the 

overall eligibility rating of each pilot-rated applicant having 350 or more 

hours of logged flight time. A cursory review by Cobb of 

biographical-questionnaire response data for several hundred pilot-rated 

ATCS trainees recruited during t969 revealed that about half of them 

possessed no more than a private pilot license and 350 to 500 hours of 

logged flying time, and less than 10 percent had t,OOO hours or more (22). 

In preparing for a direct study of the issues during t972, Cobb and 

Nelson (22) contacted a number of Academy instructors and other long-tenured 

ATCS personnel and solicited their opinions regarding the validity of pilot 

experience for selection purposes. Each was consulted on an individual 

basis and granted assurance of anonymity. According to Cobb and Nelson 

(22), few expressed satisfaction with the current standards, several stated 

that pilot experience should not be considered in the selection process 

unless the applicant held a commercial license with an instrument rating, 

and some felt that all pilot experience should be disregarded. 

Of all the discussants, those who had entered civilian ATCS training 

shortly after World War II seemed to have the strongest opinions (22). Many 

with military service as Airport Tower Operators said that pilot experience 

26 
had always received unwarranted emphasis; they felt that the selection 

standards used for several years after 19~5 tended to favor the pilot-rated 

applicants, and that the military controllers frequently represented a 

minority of the ATCS-trainee recruits because they generally experienced 

greater difficulty in establishing highly competitive eligibility ratings. 

Rowever, most of the long-tenured ATCSs who had served as pilots during the 

war felt that their candidacy for the military pilot-training programs, and 

commissioned-officer status after graduation, had been based on 

exceptionally high qualification standards (e.g., mental abilities and/or 

education, etc.). Some alleged that the majority of the pilot-rated ATCSs 

recruited during those years possessed more than t,OOO hours of flying time, 

usually with a great deal of navigational training and experience, and that 

the validity of that experience was manifested in the relatively low 

attrition rates of the pilots for all phases of the ATCS training program. 

Several claimed that the then-current issue regarding the use of pilot 

experience as a selection factor would never have arisen "if the standards 

had remained sufficiently high to preclude the entry of so many 

'leisure-time' or 'Sunday' pilots" (22). Unfortunately, Cobb and Nelson 

(22) were unable to locate any factual information concerning the 

backgrounds and training progress of ATCSs recruited during the immediate 

postwar years. Hmvever, it was commonly acknowledged that military pilots 

with extensive flying experience and navigational knowledge represented 

progressively smaller proportions of the pilot-rated personnel selected each 

year since about 1955. 

Increased skepticism regarding the validity of pilot experience for 

selection purposes (22) followed publication of the report of the Air 

Traffic Controller Career Committee in January 1970 (t). The committee 

report stated that no evidence could be found indicating any type of pre-FAA 

experience other than ATC work to be useful for prediction of FAA ATCS 

training progress or subsequent job performance. The report (t) recommended 

"elimination of credit for pilot experience" in the selection process. The 

same recommendation was made in a July t970 contract report to the FAA by 

Colmen ('2.5). However, neither of the two investigative bodies cited any 

studies other than those by CAMI as a basis for their conclusions and 

recommendations concerning pilot experience, and those cited studies did not 

necessarily imply that all such experience should be completely disregarded 

(22). None of the studies had focused directly on the issue of pilot 

experience; none included determination of the attrition-rate probabilities 

for ATCSs relative to their flying time or types of ratings held (e.g., 

private license, commercial license, instrument rating, air transport 

rating, etc.): and the inter~ction effects of age, aptitude, and education 

on the validities of pilot experience and other types of experience had 

never been assessed and compared. Thus the comprehensive longitudinal study 

by Cobb and Nelson (22) was undertaken to obtain such information and 

thereby minimize much of the conjecture that would otherwise arise in the 

formulation of future standards relating to the evaluation of prior 

experience in the selection of ATCS trainees. 

, 

That longitudinal study of 4,092 ATCS trainees examined the validities 

of various types of aviation-related experience, separately and in 

27 
combination, for prediction of success in FAA ATC work. Success was defined 

as retention status within the ATC system several years after entry into 

training. Of the ~,092 ATCSs, 1,740 entered Academy basic training during 

September t960 through August t963, before the CSC ATC battery became 

operational in the screening of most applicants. The remaining 2,352 ATCSs, 

the majority of whom were selected from among aptitude-screened applicants, 

entered Academy training during t969. Both groups entered prior to 

establishment of the current standard under which eligibility for training 

is restricted to personnel no older than age 30. The obtained results 

clearly demonstrated that success in FA~ ATC work was far more contingent on 

entry age than on type of aviation-related experience, level of aptitude, or 

level of education. The findings led Cobb and Nelson (22) to suggest that 

ATCS applicants who meet the existing age and aptitude screening standards 

should not be awarded credit points toward their eligibility ratings for any 

type of experience other than ATC work (see Figure 7), and that even the 

latter should be conservatively assessed and weighted in the selection 

process, particularly with respect to military control experience that 

involved no instrument flight rule (IFR) operations. Cobb and Nelson (22) 

noted parenthetically that if such a procedural change were followed, an 

indirect result would likely be a relative improvement in the competitive 

ranking of women and minority candidates who, for various sociocultural 

reasons, probably do not obtain the types of pre-FAA experience for which 

credit is given in selecting ATCS candidates. 

Candidates having only pilot experience when they entered ATCS training 

during either of the two widely separated time periods had unusually low 

retention rates, even lower than those of groups having no aviation-related 

experience of any type. Speculation that many of the pilot-rated ATCSs 

might have volitionally attrited in order to take jobs of higher pay or jobs 

more compatible with their flying interests, prompted a search of the 

standard personnel records. of all FAA employees; only t4 of the 254 

attrited pilot-rated ATCSs of t969 were still in the FAA (in non-ATC jobs) 

at the beginning of t973. Of the t4, 6 were aviation safety officers (5 of 

whom were GS-t2's); t was a GS-t2 in an educational training program, and 

the other 7 were in various jobs (e.g., electronics technicians, flight data 

aids, wage board employees, clerks, etc.) with lower pay grades (22). 

Unfortunately, data were unavailable for a similar followup study of the 

remaining 240 attrited pilots who had left the F~~. 

Thus ATC experience that involved only visual flight rule (VF~) 

operations proved to be considerably less valid than ATC-lFR experience for 

prediction of success in either the En .Route or Terminal option. Cobb and 

Nelson (22) therefore concluded that, when possible, all En Route and 

Terminal trainees should be selected from among the best qualified of the 

aptitude-screened candidates younger than 3t who possess pre-FAA IFR control 

experience. 

In a later CAMI report by Lewis (35), the feasibility of using scores 

on the Occup~tional Knowledge Test (OKT), a test containing questions on 

general ATC information to determine the quality of an applicant'? ATC 

28 
Type Experience 

For Which a 

Rating Was Held 

Unknown 

Pilot Experience 

Only 

Pilot With 

Communications 

Pilot With 

Pre-FAA ATC 

Pilot With Both 

ATC & Communications 

ATC 

Only 

ATC With 

Communications 

Communications 

only 

No ATC, Pilot, or 

Communications 

TOTAL 

Total Pilots 

With No ATC 

Total Pilots 

With ATC 

Total 

Non-Pilots 

With ATC 

Total Subjects With No 

ATC or Pilot 

33.3% 3 

49.3% 71 

52.4% 458 

72.7% 11 

67.9% 81 

67.7% 849 

55.7% 79 

54.3% 94 

52.1% 706 

52.0% 529 

68.5% 92 

66.7% 928 

52.3% 803 

Total 

Sample 

•••2•0•• 9% •• E-~2~~~~~;~· ~-..,....---5_8_. 5_% ____ ..JI2, 352 

Figure 7. Attrition and retention rates by pre-FAA 

experience categories for 2,352 entrants into the 

Academy's En ~oute and Terminal basic training 

courses during t959 (adapted from Cobb and Nelson, 

l974, ref. 22). 

29 
experience prior to g1v1ng extra experience points (43) was examined. The OKT 

had been developed from a pool of test items (some specially devised, others 

drawn from existing FAA Academy instruments) with the intent of being 

"job-knowledge specific" (37,43). Its initial use had been intended for screening 

applicants with previous ATC experience who would enter at higher grade levels. 

The Lewis study revealed that assigning extra credit subjectively on the basis of 

verified experience (the quality of which was usually difficult to define) 

resulted in a failure rate of 7.6 percent while assigning extra credit on the basis 

of OKT scores would result in a failure rate at the FAA Academy of less than half 

that rate. Consequently, Lewis (35) concluded that using the OKT as a basis for 

assig~ing extra credit for specialized experience was more fair than using 

verified experience. 

Summary. Although CAMI's early followup studies provided ample 

evidence attesting to the validity of ATC experience as a selection 

variable, the same studies indicated all other types of aviation experience 

(e.g., pilot, navigator, air defense surveillance, etc.) to be virtually 

worthless for prediction of training outcomes or retention in FAA ATC work 

several years subsequent to recruitment (l5,20,22,49,50). More importantly, 

variables reflecting experience in aviation-related areas other than ATC 

(and also in fields unrelated to aviation) were frequently found to 

correlate inversely (sometimes at statistically significant levels) with the 

criterion variables. This was particularly true with respect to 

aircraft-pilot experience. Moreover, when statistical procedures were used 

to theoretically nullify the effect of age, the validity coefficients of 

variables representing "years of pilot experience," "logged hours," and 

"pilot ratings" were found to be in either the low negative or very low 

positive range. Such findings prompted a committ~e, established by t~e FAA 

Administrator in late t974 to ascertain methods of improving the ATCS 

selection and training programs, to recommend that selection procedures-be 

revised to preclude consideration of any type of preemployment experience 

except that directly involving air traffic control (24). Such a 

recommendation, however, runs counter to the esc's traditional policy of 

evaluating virtually all types of preemployment experience in the selection 

of personnel for almost any occupational specialty wit~in the Federal 

service. Cobb, Young, and ~izzuti (24) expressed the view that the FAA 

should nonetheless press vigorously for changes whereby aviation experience 

other than ATC would be at most very conservatively weighted in the 

selection process. 

Education as a Selection Factor 

The ATCS selection programs of all time periods have included the 

mandatory requirement that an applicant either hold a high school diploma or 

provide evidence (e.g., a General Education Development (GED) certificate) 

of an educational background deemed equivalent to that of a typical 

graduate. Education beyond the high school level (although not mandatory) 

has traditionally received significant weighting, directly or indirectly, as 

30 
a factor in the derivation of each applicant's overall eligibility rating. 

Selection programs have invariably included provisions whereby the "general 

expetience" requirements, specified for applicants not having backgrounds in 

aviation, could be met wholly or in part by the substitution of 

college-level education. Regardless of experience, however, applicants with 

4-year college degrees have usually been provided a variety of standards 

helpful in establishing training candidacy. As mentioned earlier, there was 

a period during which college graduates with records of superior academic 

achievement were screened in terms of an aptitude-test-score standard that 

was considerably below that designated for screening of their comparably 

experienced and otherwise equally qualified colleagues. Also, a similar 

policy prevailed at one time that pertained to all college graduates, 

irrespective of academic records. However, the greatest emphasis of 

education as a selection factor was during t97t and t972 when applicants 

with 4-year college degrees having at least t year of graduate work and \2 

months of specialized ATC experience could be granted waivers of the 

aptitude-test-screening phase and also be appointed to training at grade 

GS-9 rather than GS-7 (24). 

Throughout the history of the CAA and the FAA, education has received 

notable consideration as a factor in the selection of ATCS trainees. 

However, virtually all the selection procedures relating to education except 

those concerning records of superior academic achievement have pertained to 

levels of education, or years of education completed. The types of college 

studies (e.g., college courses, areas of major and minor study, etc.) 

pursued by the applicants had generally received little or no consideration 

(24). While relevant experience has usually been deemed more important than 

education as a selection factor, applicants lacking qualifying preentry 

experience, but meeting other prerequisites, have generally been allowed to 

substitute college education (as measured by years) for experience, in 

accordance with differential rates prescribed for the various types of 

experience. 

Although the selection procedures pertaining to education have varied 

from time to time, they have consistently reflected an implied assumption 

that success probabilities in ATC training and work tend to vary in 

accordance with levels of education attained by personnel considered equa lly 

qualified in other respects. However, the belief that educational level is 

indeed appropriate and valid for selection purposes had no apparent research 

base. To the contrary, various phases of early ~MI research (all data 

based on trainees who entered ATCS training in the decade of the t950's) on 

ATCS selection in which level of education was included as a variable for 

"peripheral study'' in analyses relating to the validation of age, 

preemployment experience, and aptitude-test performance indicated that the 

training attrition rates of ATCS personnel tended to increase (rather than 

decrease) in accordance with the preentry levels of education (\4,20,22,49). 

Several unpublished C&~I studies involving trainees recruited during various 

time periods had shown that college graduates generally had significantly 

higher attrition rates than selectees having either high school diplomas 

only or t year or less of college (24). 

31 
Such findings, however, did not necessarily imply the need for 

reformulation of selection procedures relating to education. In fact, the 

early findings could not be reliably interpreted because they were 

undoubtedly confounded by (unassessed) interaction effects of age, 

experience, aptitudes, and other factors considered in the selection 

process. Virtually all the early (pre-t975) CAMI validation data pertaining 

to education were derived in conjunction with research undertaken primarily 

for other purposes. Some of the CAMI studies in which level of education 

had been included as a variable for ancillary study involved determination 

of the coefficients of correlation for the educational variable versus 

Academy training-performance measures and other criteria (t4,20,22,49,5t). 

Certain phases of research also had included the determination and 

comparison of attrition rates of ATCSs categorized in terms of educational 

level (22). In none of these studies, however, were analyses conducted to 

assess the effects of other selection factors on the validity of the 

educational variables or the influence of the latter on the validities of 

the former. Moreover, selection procedures bearing on education had 

traditionally included consideration of level only, and, due in part to that 

fact and the ready availability of data not requiring transposition, CAMI 

investigators invariably refrained from dealing with other aspects of 

education when conducting research undertaken primarily for other purposes. 

Thus, a major study (24) specifically focused on education was 

undertaken for three basic purposes: (i) to assess the validity of level of 

education as a selection factor, separately and in combination with other 

factors officially considered in the selection of ATCS trainees; (ii) to 

determine whether data and information relating to other aspects of 

education (e.g., recency, major courses of study, etc.) were sufficiently 

related to training attrition-retention status to warrant consideration in 

the establishment of eligibility ratings; and, if so, (iii) to derive a set 

of factor weights, reflecting their relative performance, for recommended 

use in future revisions of the ATCS selection standards. 

Series of analyses were conducted on data pertaining to 2,352 ATCS 

recruits who entered the Academy basic training phase in t969 (t,858 En 

Route and 494 Terminal trainees). The study (24) revealed all educational 

variables, both before and after consideration of effects associated with 

age and other selection factors, to be negligibly and/or inversely related 

to success in ATCS training as defined by Academy graduation status and/or 

retention in the ATC system 3 to 4 years following recruitment (see Figure 

8). 

The l8t college graduates among the 2,352 recruits had a higher Academy 

attrition rate (30.9 percent) than any other subgroup, and 208 whose highest 

level of education was reflected by a GED certificate for high schoo~ had 

the next highest Academy attrition rate (24.5 percent), whereas the lowest 

rate (t8.0 percent) pertained to 87? having high school diplomas only, 

followed closely by the rate of those having less than 1 full year of 

college (t8.3 percent). Post-Academy (i.e., facility training) attrition 

rates ranged from t6.3 to 26.5 percent and followed a somewhat similar 

rank-order pattern (24). 

32 
Figure 8. ~etention rates by level of education and type of 

rated pre-FAA aviation-related experience for 

2,349 selectees who entered Academy basic training 

in En Route or Terminal ATC procedures during 

t969. Rates reflect proportions of ATCSs in each 

subgroup who were still in FAA ATC work as of 

January t973 (from Cobb, Young, and Rizzuti, t976, 

ref. 24). 

Major courses of study listed by some 925 of t,255 ATCS trainees who 

attended college were found to have little potential for prediction of 

training outcomes (24). The overall retention rate as of January t, t973, 

for the t,265 former college students was 56.7 percent. When categorized on 

the basis of major studies, only those (N=t4t) majoring in the social 

sciences were found to have a retention rate differing significantly from 

that of the combined categories. Only 4t.8 percent of the t4t social 

science majors were still in FAA ATC work at the beginning of t973. 

Moreover, 53 recruits for whom major courses of college study were judged as 

being more directly related to aviation than were the majors of all others 

were found to have a retention rate of 56.6 percent, only one-tenth of a 

point lower than that of the entire group of former college students. 

33 
Summary. Thus, CAMI research through the mid-t970's found no 

educational variable that evidenced a significant interaction effect on the 

validities of other selection factors. In addition, all types of 

aviation-related experience except ATC were found to be grossly unreliable 

for prediction of training outcomes. These and other findings led Cobb, 

Young, and Rizzuti (24) to suggest that candidacy for ATCS training should 

be restricted to aptitude-screened applicants no older than 30 and that it 

would also be advisable to discontinue the award of credit points toward 

eligibility for all types of education and/or preentry experience except ATC 

experience. 

Sex as a Factor in Performance and Attrition 

While it had long been a governmental policy to provide equal 

employment opportunity in the Federal service to all persons, regardless of 

race, color, religion, national origin, or sex, a major emphasis on this 

policy was contained in Executive Order tt478 issued in August t969, wherein 

the head of each department and agency was directed to "establish and 

maintain an affirmative program of equal employment opportunity" to 

eliminate all remaining vestiges of discriminatory practices. Based on the 

Ffu\'s interest and participation in the overall program to eliminate sex as 

a discriminating factor in the selection of new Federal employees, a 

comparative study of female and male ATCS trainees was undertaken (20). The 

study was also prompted by the fact that women had never represented more 

than a very small proportion of all personnel directly involved in air 

traffic management. Since experience is heavily weighted in establishing an 

applicant's eligibility rating, the "best qualified" by normal standards are 

usually male veterans with experience in military ATC work or as pilots 

(t3,t4,46,49,50). It was therefore contemplated by Cobb in the early t970's 

that comparative analyses of the various types of data available for groups 

of female and male trainees would yield findings of value to the FAA in its 

formulation of future recruitment, selection, and training programs. 

As part of his comprehensive research program (t8,t9), Cobb and his 

associates had administered various aptitude tests, on an experimental 

basis, to all but three of the successive incoming classes of the Academy's 

basic training courses in Terminal, En Route, and FSS work during a 17-month 

period (November 20, t968, through March 27, t970). CAMI was provided a 

report on each trainee at time of entry into the Academy, reflecting types 

and amounts of preemployment experience, facility assignment, the overall 

eligibility rating (used for selection purposes), pay grade, and other 

information; the report on each trainee who took the operational CSC ATC 

test battery also included all part scores and the composite measure of 

performance. 

Although participation in the experimental testing program was not 

mandatory, few declined to take part (20). Only 4t0 (t0.7 percent) of the 

3,843 trainees were not examined, and the majority of the 4t0 were in 

34 
classes for which testing sessions were canceled in order to avoid holiday 

travel conflicts. Generally, each group was examined on the day of arrival 

at the Academy. No more than 3 hours could be allocated for each testing 

session, and adherence to training schedules precluded more than one session 

per class or group. Inasmuch as the overall project specified that the 

potential of many different types of tests be explored as predictors of 

training performance, the groups of tests selected for experimental 

administration were intentionally varied. At least t week, and sometimes 2, 

intervened between incoming groups. Each group was administered only five 

to seven instruments, but periodic modification of the battery ultimately 

resulted in the collection of response data on samples of different sizes 

for 36 different tests or subtests; these yielded ~t performance measures 

(20). 

The study compared age, education, pre-FAA experience, aptitudes, 

training-course performance measures, and post-Academy attrition rates of 

the 83 women who entered basic ATC training at the FAA Academy during the 

t7-month period with those of various samples of the 3,760 males who entered 

training during the same period. The study (20) revealed no significant 

differences between the means of the female and male trainees with respect 

to age and educational level. When samples of the 83 women were compared 

with samples of male trainees in terms of performance on 36 different 

apptitude tests, only four mean differences, all of which favored the women, 

proved statistically significant. Only 45.8 percent of the 83 women had 

pre-F~\ ATC-related experience, while such experience was possessed by 63.9 

percent of a sample of 798 men; the difference was statistically 

significant (p < .Ot). The means of the training course grade averages of 

the two groups differed by only three-tenths of one point, and there was no 

significant difference between the Academy attrition rate of 20.5 percent 

for the women and 23.2 percent for the 798 men. However, the groups 

differed markedly with respect to post-Academy attrition rates; 48.5 

percent of the 66- women who completed Academy basic training were no longer 

in the air traffic management system as of December t97t, whereas only 22.5 

percent of the 6t3 men (within the sample of 798) who graduated from the 

Academy were subsequently attrited (20). 

These attrition rates, which showed (i) no sex differences in the 

proportion of trainees who completed FAA Academy training, but (ii) a 

percentage of women who subsequently left ATC work that was over twice that 

of male graduates, led to several studies of sex differences in job 

attitudes and attrition rates (38,39,40). In one of these, the 56 women who 

entered the Academy between December t968 and November t970, and who were no 

longer with the FAA as of June t972, were matched on several variables with 

male attritions who had entered the Academy at the same time. Reasons for 

attrition were obtained from job-exit forms, telephone interviews, and a 

questionnaire. The majority of trainee attritions could be accounted for by 

three reasons: training difficulty or failure, family, and other 

employment. The category that accounted for most of the difference in 

attrition rates between the sexes was family-related (marriage, children) 

attrition cited by about one-third of the women, a finding that agrees with 

results of other studies of different occupational groups (39). 

35 
Summary. CAMI studies on sex as a factor in Academy performance have 

shown, for the relatively small proportion of women entering ATCS training 

around t970, no differences from men in age, educational level, general 

aptitude factors, Academy training performance, and Academy attrition rates. 

However, significantly fewer women had prior ATC-related experience, and a 

significantly higher proportion of women attrited before reaching the full 

performance level. The difference between the sexes in reasons for 

attrition was mostly due to family-related reasons for women. 

~esearch on Military ATCS Trainees 

CAMI has had a long-standing interest in the selection and training of 

military ATCSs based in the fact that an applicant pool of former military 

controllers has always represented a prime source for the selection of FAA 

ATCS trainees. Aside from other reasons, these recruiting practices have 

prompted the FAA to maintain some awareness of the effectiveness of the 

controller selection-and-training programs in the u.s. Air Force, Army, 

Navy, and Marine Corps (t7). 

~lans for the first of the two 'CAMI investigations regarding military 

ATCS trainees were initially conceived in t955, when representatives of the 

Glynco Naval Air Station, Georgia, visited CAMI for indoctrination regarding 

the underlying research, development, and effectiveness of aptitude testing 

and other procedures used in the screening and selection of applicants for 

FAA ATCS training. Naval officials subsequently discussed the possibility 

of being permitted the use of the operational battery of esc tests for 

experimental administration and validation at Glynco. Although a number of 

policy reasons precluded this approach, Cobb suggested an alternate plan, 

subsequently accepted, involving the seven commercially published tests that 

had been validated in previous research with FAA trainees (t7). After 

completion of the Glynco study (t6), officials of Keesler Air Force Base, 

Mississippi, asked that a parallel study be conducted on samples of Air 

Force and Army ATC trainees. 

The selection of tests for validation at the two training facilities 

was predicated on the findings that CAMI had obtained in previous research 

with FAA ATCS trainees. As mentioned earlier, a total of eight non-CSC 

instruments (seven commercially published tests and the Air Traffic ~roblems 

test), had been identified as yielding a number of different and valid 

composite measures for prediction of FAA ATCS performance criteria. Each 

composite score validated at a statistically significant level for 

prediction of the training measures. Inasmuch as the Air Traffic ~roblems 

test was subsequently designated as a esc test, existing policies precluded 

its release for experimental use with military trainees. It was assumed 

that the remaining seven tests would constitute an appropriate battery for 

experimental studies involving military ATCS trainees (t7). 

Although two of the seven commercially published tests which were 

experimentally administered to the military ATCS training schools 

36 
consistently failed to correlate at statistically significant levels with 

the training-performance measures of every group (CTMM Analogies and CTMM 

Coins), composite scores based on the entire seven-test battery correlated 

with the academic plus laboratory grades of every group at somewhat higher 

levels than any of the measures based on combinations of test scores. Yet, 

in every instance, the validity of the "commercial seven-test composite" 

score was closely approximated by that of a composite measure reflecting 

performance on DAT Space Relations, DAT Numerical Ability, DAT Abstract 

Reasoning, and CTMM Inference (17). 

Composite scores of both types correlated with the training-course 

performance measures significantly better than did the Air Force's General 

Aptitude Index (GI) and the Marine Corps' Military Screening and 

Classification (~1SC) test score, and at about the same level as the aptitude 

screening measures used by the Army and Navy. Despite the high degree of 

comparability between the validities of each experimental composite and the 

~1SC scores of the Army and Navy trainees, the results of multiple 

correlational analyses indicated that the experimental measures for these 

trainees, as well as for the airmen and marines, could have been used in 

combination with the MSC scores to attain some degree of improvement in the 

respective ATCS selection programs (17). However, the benefits stemming 

from such a procedure would have been considerably less for the Army and 

Navy than for the Air Force and Marine Corps. Moreover, while these studies 

were undertaken to determine the effectiveness with which various 

experimentally derived aptitude test measures might be used to improve 

military ATCS trainee selection procedures, the most important finding was 

that the screening potential of existing MSC aptitude-test scores could be 

more fully exploited to achieve that end 0. 7). For reasons unknown, but 

perhaps due to recruiting demands, t6.5 percent of the Navy trainees, t4.8 

percent of those in the Air Force, about 5 percent of the Army selectees, 

and one Marine were assigned to military ATCS training even though their MSC 

scores were below the normally prescribed minimum (which was t10 on the 

different test batteries employed by the Army, Navy, and Marine Corps, and 

65 in terms of the Air Force GI). About 42 percent of the t38 men selected 

from these lower MSC-score categories either failed or marginally passed 

their training courses compared with t8.2 percent of the other 1,085 

military ATCS trainees involved in the study. Moreover, other findings 

suggested that the recommended aptitude-screening standards could be raised 

by several points to increase their effectiveness. For example, MSC scores 

of less than tl5 reflected the aptitude levels of 234 Army, Navy, and Marine 

trainees, and 5t airmen possessed a GI score of less than 70. Over 40 

percent of these 285 students either failed or marginally passed training, 

whereas only t5 percent of the remaining q33 did so. The initial screenout, 

or disqualification, of every trainee having either an MSC score of less 

than ll5 or a GI score under 70 would have rendered the commercial composite 

measures virtually useless for secondary screening purposes (\7). 

Thus, on the basis of these results, Cobb (\7) concluded that the Army, 

Navy, Air Force, and Marine Corps had the capability, if desired or 

required, of upgrading their screening of ATCS personnel without new or 

37 
additional tests, by establishing higher m1n1mum MSC requirements. Any 

changes in the military requirements would be of direct interest to the FAA 

since the agency has and will probably continue to select significant 

proportions of its ATCS trainees from among those applicants who have 

pre-FAA ATC experience and who also are able to qualify on the CSC ATC 

Aptitude Screening Test battery. At the present time, 210 is the minimum 

passing score on the battery. Such a screening standard (roughly equivalent 

to an MSC score of 125 and a Gl score between 75 and 80) reflects a high 

degree of selectivity, such that numerous unpublished studies by Cobb had 

demonstrated that a downward revision in the aptitude-test screening 

standard of 10 to l5 score points (but no more than 20) was feasible and 

should be considered if the recruitment of personnel for FAA training ever 

reached a critical stage (l7). On the basis of the results obtained in this 

study and those of previous investigations, Cobb (l7) predicted that 

approximately one-half of the military trainees selected under these 

military ATCS selection standards would have been able to meet then-current 

(l97l) FAA aptitude screening requirements; only about one-third of the 

FAA's applicant population prior to 1964 would have been able to do so. 

Moreover, if military cutoff scores were raised, for any reason, from 

then-present (l97l) levels to MSC scores of 115 and to Gl scores of 70, 

approximately two-thirds of the military contr.ollers who qualified at those 

levels would qualify on the FAA's aptitude screening battery (l7). 

Summary. CAMI research on military ATCS selection procedures produced 

two major findings: (i) The same commercially available aptitude tests used 

in the development of the FAA aptitude screening tests were valid for 

predicting training success for military trainees and, if added to existing 

military tests, would improve prediction; and (ii) the effectiveness of 

military selection could be improved simply by increasing minimum cutoff 

scores on existing military screening tests. As a byproduct of this 

research, Cobb was able to outline the relationship between military 

selection/training procedures and the screening and entry of ex-military 

personnel into the FAA ATCS program. 

Research on Alternative Aptitude Screening Measures 

The early research in which six CSC tests were initially validated also 

yielded appreciable validities for a number of other CSC tests and several 

commercially published, copyrighted instruments. The latter group included 

several tests that apparently involved a speeded perceptual-discrimination 

factor and some that pertained to either coding skills, comprehension, rapid 

integration or processing of information, or memory (l9). Although none of 

these .tests appeared in the final group that the multiple regression 

analyses indicated most useful for selection purposes, the results led Cobb 

and Mathews (l9) to suspect that the instruments were measuring important 

ATC-related aptitudes, albeit inadequately. Such findings, supplemented by 

those obtained for a number of different spatial tests, were interpreted as 

illustrating the need for development of tests "tailored" to fit the ATCS 

selection purpose more precisely. 

38 
The Directional Headings Test. Hhile none of the various spatial tests 

included in CAMI's numerous experimental batteries had failed to validate at 

statistically significant levels, the validities of each had generally been 

much more variable from sample to sample than for nonspatial tests. 

Parenthetically, this also applies to CSC Booklet St of the operational 

screening battery. Cobb had concluded early on that a "visual imagery" type 

of speeded spatial ability was a major determinant of ATCS performance but 

was unable to locate an instrument fully appropriate in this respect. The 

development of a special test, the complexity of which would have required a 

major research effort, was not underta~en during the t960's due to other 

research commitments having higher priorities (t9). 

However, early in t970, the Directional Headings Test (DHT) was under 

"in house" development and experimental validation by Cobb on the basis that 

the aptitude screening process might be further improved through more 

adequate assessment of the applicants' speeded perceptual-discrimination and 

coding (or' decoding) skills. In conceiving the type of task ultimately 

embodied in Part I of the DHT, initial efforts focused on the use of 

diagrams simulating a navigational compass. However, the pictorial approach 

was abandoned on the hypothesis that if the data pertinent to the solution 

of each problem were presented in a different format, such as described 

below, the test would be more difficult and therefore provide better 

opportunity for individual differentiation (t9). 

The DHT was a three-part test (in the final form, Part III was dropped) 

in which the examinee is allowed a total of only 90 seconds for the solution 

of 60 items, or problems, of each part (t9). In each problem, the examinee 

is presented one, two, or three "bits" of information relating to the 

cardinal points on a mariner's compass. For example, the letter "N," the 

symbol "A," and the notation "360" each denote "North." Similarly, the 

letter "E," the symbol">," and "090," either separately or in combination, 

denote "East." Other letters, symbols, and degrees correspond to "South" and 

"Hest." In Part I of the test, the examinee must rapidly interpret and 

collate the bits of presented information in prder to ascertain whether the 

data are of a conflicting nature and, if not conflicting, then determine the 

directional heading to which they correspond; in Part II, the examinee must 

determine the exact opposite of the heading; and, in Part Ill, the examinee 

must ascertain the exact opposite of the directional heading while being 

subjected to aural distraction. In each item of Form A, the bits of 

information are followed by one of five questions: "North?," "East?," 

"South?," "Hest?," or "Conflict?." Two response categories are offered, 

"Yes" or "No." Approximately one-fourth of the items present "conflicting" 

data. For example, if the letter "S" were presented in an item of Part I 

with the symbol":>" and/or "270" and if the question · were "Conflict?," a 

correct answer would be indicated by marking the space under "Yes." On the 

other hand, the same conflicting data presented with "West?" (or "North?," 

"East?," or "South?") would warrant a "No" answer. 

The first preliminary version of the test consisted of only one part, 

with the task being essentially the same for all 50 items (t9). Small 

39 
groups of Academy ATCS trainees were examined with the instrument and, 

although no validation analyses were possible at that time, considerable 

range and variance were found in the distribution of scores. Moreover, 

during test sessions, some individuals in every group appeared to become 

rather confused, or frustrated, when confronted with those items in which 

"conflicting" bits of information were presented and also hesitant in 

marking either "Yes" or "No" to many of those items where the questioned 

direction (e.g., "North?") failed to conform to the heading indicated by the 

data provided. When the CSC ATC battery was being validated some 8 years 

earlier, reactions of much the same type had been noted for many of the 

trainees during their assessment with CSC 135, Following Oral Directions. 

Inasmuch as esc 135 proved to be one of the most valid components of the 

screening battery, Cobb hypothesized that many of the trainees who had 

performed poorly on the instrument might have done so because they had a 

"low frustration tolerance level." Although the latter phrase and the 

hypothesis to which it alludes were rather loosely formulated, they grossly 

reflected the reasoning that led to the development of Parts II and III of 

the DHT ( t 9) • 

As mentioned earlier, DHT Part Il is similar to Part I except that in 

each item the examinee is asked whether a specified direction represents the 

direct opposite o~ the heading (19). Part Ill is li~e Part II but the 

examinee is subjected to possible distraction by the aural presentation of 

the randomly arranged words, "West," "South," "East," "North," and 

"Conflict." The resulting three-part instrument, in which the examinees were 

offered no response categories other than "Yes" or "No," was designated as 

CAMI Directional Headings Test--Form A. 

An alternate version of the test, Form B, was eventually developed: it 

offered five response categories (t9). In each item of the latter, the 

"bits" of information are presented in the same manner as in Form A but the 

"question element" does not appear and the examinee merely indicates the 

answer he or she deems correct by marking a response space unde~ one of the 

five columns labeled, "East," "South," "West," "North," and "Conflict." 

Form A of the DHT was administered by Cobb and Mathews (t9) on an 

experimental basis to a total of 586 students as they enrolled at the FAA 

Academy from January 20, 1970, through March t3, 1970, in either the basic 

En Route or Terminal training course. Form B was administered on a similar 

basis to t99 trainees, all of whom entered the En ~oute course on March 27, 

1970. The vast majority of the 785 trainees examined with either Form A or 

Form B were new hirees and none possessed an FAA ATCS certificate; most had 

been selected for training on the basis of competitive ratings from among 

candidates who met exceptionally high qualifying standards in terms of 

operational aptitude test screening scores and/or evaluations of pre-FAA 

experience. Despite these prescreening effects, the DHT scores correlated 

.4t with an overall measure of training performance. Moreover, over ~4 

percent of the 15 examinees who failed the training course scored no higher 

than ?.9 on the DHT, whereas over 85 percent of the graduates scored 30 or 

higher. Reliability of the instrument, as determined by correlating the 

40 
scores based on even-numbered items versus scores based on odd-numbered 

items, was .93. The DHT was made available to EPA, the private company that 

was performing an ATCS selection study for the FAA as mentioned earlier. In 

their final report (~l) based on samples of journeyman controllers with 3-lO 

years of experience, EPA researchers noted t~e effectiveness of the DHT in 

predicting job success by citing it as one of the best of the large numbers 

of aptitude tests they evaluated. Thus the promising DHT findings obtained 

by Cobb and Mathews (l9) with ATCS trainees w~e independently confirmed 

with a different group of journeyman controllers. 

Based on the above findings the DHT has been included in current efforts 

to develop a new ATCS screening battery (5). The test has shown good predictability, but in its present highly speeded form is not amenable to ordinary OPM 

national testing procedures (5). Efforts, perhaps, should be directed toward 

altering the DHT to a usable form or incorporating it in another instrument. 

The Multiple Task Performance Battery. While the CSC ATC test battery 

does an efficient job of identifying those individuals who possess the 

"elemental" skills and knowledge necessary to becoming a satisfactory 

controller, it does not measure a particular ~ind of ability that may be 

said to be a defining characteristic of a good controller--the ability to 

perform several different tasks simultaneously (tl). Thus, undoubtedly a 

number of trainees are eliminated from the ATCS training program, not 

because these trainees lack information in the academic sense, but because 

of an apparent deficiency in their skill at the concurrent, time-shared 

performance of a variety of tasks, viz, they cannot put the information 

together and perform satisfactorily. IE this is true (and it is a widely 

held belief among FAA Academy instructors), then a technique that provides 

an objective, reliable index of the ability of an applicant to time-share 

multiple tasks of relevance to the job of an ATCS would be of value as an 

adjunct to the existing selection devices (ll). 

During the period from May t970 to January l97l, exploratory studies 

were carried out by Chiles and his coworkers to examine the potential 

usefulness of a performance measurement device as a predictor of the future 

performance of ATCSs. Five groups totaling 229 ATCS trainees were tested on 

the CAMI Multiple Task Performance Battery (MTPB), and the predictor scores 

that were derived from the performance battery were correlated against a 

criterion provided by FAA Academy instructors (tl). 

The MTPB was originally designed for the Air Force as a device for use 

in research on complex performance of the sort demanded of aircrew personnel 

(tO). The elements of the MTPR were selected to provide objective measures 

of "psychological or behavioral functions" of relevance to Air Force 

operations. The functions measured by the MTPB include monitoring, 

information processing, mental arithmetic, visual discrimination, and 

interindividual interaction in the execution of procedures (see Figure 9). 

These functions would appear to be relevant not only to aircrew activities 

but to complex jobs in general and to the job of the ATCS in particular. 

Moreover, the tasks, as routinely used over a number of years, have been 

41 
• • 

:;) 

. . ~ 

••••• 

• • • 

0 

• D r ) 

• • • • 

Figure 9. The CAMI Multiple Task Performance Battery. The 

upper photograph (~) depicts the console used in 

the studies discussed in this report, and the 

lower photograph (B) shows the current version of 

the test. 

42 

A 

8 
structured to impose varying levels of demand on the individua l with respect 

to the requirements for time-sharing . Good performers on the MT~B are those 

individuals who not only possess ability on the individual tasks but, a lso, 

are readily able to shift their focus of attention from one kind of activity 

to another without disruption of the ongoing process (tt). 

The rationale for investigating the selection potential of the MTPB 

derived from the complexity of the ATC task situation with respect to the 

requirements for time-sharing. There was no particular reason to expect any 

of the individual tas~s to be predictive of ~TCS abilities even though FAA 

Academy instru~tors regarded the tasks as being generally of relevance to 

the job of the controller (tt). The nature of the MTPB is such that an 

individual who fixates on the performance of one task will almost inevitably 

do poorly on one or more of the time-shared tasks. This is especially 

evident early in learning when skill is being acquired at the detailed, 

refined performance of the individual tasks. During this first hour or so 

of learning, the task ensemble should be sensitive to differences in the 

ability of individuals to shift attention rapidly from one task to a second 

task and to quickly adopt the proper "set" for the performance of that 

second task. Thus, the intent of a set of MT~B studies conducted with ATCS 

trainees was to provide an answer to an intermediate question, viz, the 

determination of whether the approach embodied in the MTPB showed sufficient 

promise as a selection device to warrant a large-scale investigation to 

develop the supporting data that would be required to demonstrate i ts 

efficiency as a predictor of ATCS skills in terms of cost-effectiveness 

criteria (tt). 

Five studies that involved a total of 229 ATCS trainees we re under taken 

by Chiles, Jennings, and Hest (tt) to explore the possibility of using a 

performance measurement system such as the MTPB as a means for ass essing the 

potential of trainees to become fully rated ATCSs. The primary criter ion 

used in evaluating the predictive efficiency of the HTPB was the mean of 

three ratings for each trainee--one rating from each of three instructors 

per trainee. Specifically, the instructors were asked to express their 

opinion of each trainee's potential for becoming a fully rated controller by 

assigning a number from t to tOO to the trainee, with 70 being "minimally 

acceptable potential." These ratings were very easy to obtain, and they 

appeared to possess satisfactory reliability (estimated to be 0.84) (t O). 

Previous research (8,46) had also shown that instructor ratings of this 

general sort were of substantial predictive value with regard to the 

on-the-job performance of ATCSs. In addition, 40 instructors were test ed on 

the MTPB and then asked to complete a seven-item questionnaire designed to 

elicit their opinions as to the relation of the MTPB as an index of trainee 

potential (tt). 

The first study involved t9 En Route trainees; it served as a 

preliminary to the other studies in checking out training and testing 

procedures; it also permitted an examination of the appropriateness of the 

task parameters used. The second study involved 60 En Route trainees; it 

yielded a good validity coefficient against the criterion--product moment r 

43 
.54. The third study also involved Bn ~oute trainees (a total of 3t), but a 

different set of task parameters was employed. The validity coefficient in 

this study was .53. The coefficients found in both of these studies were 

lower for data from the second and third hours of testing than for the 

first. The fourth study, which involved 30 Terminal trainees and the same 

task parameters as the third study, failed to replicate the validities found 

in the second and third studies; the correlation here was near zero. The 

validity coefficient found with 89 Terminal trainees in the fifth study, 

using still a different set of task parameters, was not as large as those of 

the second and third studies, viz, .24; however, when the MTPB performance 

index was based on measures judged to be more appropriate in relation to the 

changed task parameters, the correlation was a comparable .46. 

The opinions of the instructors, as reflected in their responses on the 

questionnaire, supported the conclusion that the MTPB exhibited substantial 

content validity as a measurement system of relevance to the job of the 

controller (tt). 

It was concluded that the task parameters used in the first study (and 

retained in the second study) were closer to optimum than were any of the 

modifications used in the third, fourth, anq fifth studies. The method of 

computing the composite index of performance (via equal weight to all tasks 

in terms of the variance of the composite index) was judged to be the best 

technique fo.r developing an objective measure for use as a summary 

assessment of performance capability of the MTPB task ensemble. It was also 

concluded that t hour of testing yielded satisfactory reliability of the 

composite performance index (tt). 

Later, the official FAA personnel roster (dated January l, l973) was 

screened by Chiles and West (t2) to determine whether each trainee who 

participated in the earlier study was still listed as having the job code of 

an ATCS. Thus, the elapsed time from initial testing to the followup ranged 

from 2 to 2 t/2 years. Since about 90 of the trainees were tested well 

along in their training program, their tenures in the ATCS program ranged up 

to more than 3 years on the followup date. Three main questions were of 

interest: (i) How well did the MTPB measures obtained in the earlier study 

predict the retention of trainees as controllers? (ii) How well did the 

criterion (instructors' ratings) used in the earlier study predict 

retention? (iii) How well did scores on the CSC ATC Aptitude Screening Test 

predict retention of those trainees for whom scores were available? 

It is most important to note that, in general, these trainees 

represented a very select population (t2). At the time of testing, two of 

the five groups-{Studies II and III) had successfully completed the fAA 

Academy training program and had thus undergone secondary screening. In 

addition, 28 of the 6l ATCSs in Study II and 60 of the 89 trainees in Study 

V had been selected originally on the basis of having achieved satisfactory 

scores on the CSC ATC screening battery (the number of trainees who entered 

the program on the basis of esc scores was not determined for the groups in 

Studies III and IV). Thus, it would be expected that the predictive 

44 
validity of all the various measures used would be substantially attenu~ted 

and perhaps even nullified because of the range restriction produced by the 

processes previously at work in eliminating most of the trainees with 

marginal aptitudes (t2). 

Point-biserial correlations between the previously obtained performance 

measures and the retention/termination status of the trainees were computed~ 

correlations were also computed between the criterion used in the earlier 

study (instructor ratings of trainee potential) and the retention criterion, 

and between the CSC scores (where available) and the retention criterion. 

For only one group of trainees was the correlation between the retention 

criterion and the performance measure significant; this was for the subset 

of trainees (Study 11) who had not been selected on the basis of their CSC 

scores. Of the t4 correlations between the instructor ratings and the 

retention criterion, t2 were significant, p < 0.05 or better, but none of 

the correlations between the CSC test scores and the retention criterion was 

significant (t2). 

A final determination of the potential of the complex performance 

battery approach to ATCS selection would require further validating 

research. Direct support for arguing that the MTPB has predictive pow~r 

with respect to the potential of ATCS trainees derives from the results with 

the trainees of Study II. However, indirect. support is also provided in 

that (i) the instructor ratings served as a good predictor of the retention 

criterion and (ii) the MTPB was a good predictor of the instructor ratings 

in the earlier study. Should FAA selection policies for ATCSs require an 

unequivocal assessment of the predictive efficiency of performance tests, 

the results of these studies provide a basis for optimism regarding the 

expected outcome of such research (t2). 

Summary. To date two major efforts have been initiated by CA..MI 

researchers to develop alternative aptitude screening measures. These 

efforts involved the Directional Headings Test (DHT) and the Multiple Task 

Performance Battery (MTPB) . and were based on early Cru~I aptitude test 

research that suggested that measures developed specifically to screen ATCS 

trainees might profitably emphasize (i) speeded visual-spatial abilities and 

(ii) simultaneous multiple task performance requiring the ability to shift 

attention and time-share several tasks effectively. While both approaches 

showed promise, research has continued only on the DHT (5). 

Research ~elated ~ the Uniform Guidelines on Bmployee Selection 

The recent development of a set of uniform guidelines on employee 

selection procedures, rooted in the t964 Civil Rights Act Title VII, 

prompted a different type of research focus at CAMI beginning in t976, and 

coincided with both the start of a new pass/fail ATCS training program at 

the Academy and an accelerated pace of FAA-CSC activity to develop a new 

ATCS selection battery. One problem that confronted Congress in adopting 

45 
Title VII was the use of tests to select candidates for employment without 

proper evidence that the tests were predictors of job success. Congress 

attempted to produce a reasonable compromise that would eliminate 

discrimination and permit the use of tests as practical tools for employee 

selection. In Title VII, Congress allowed the use of "any professionally 

developed ability test provided that such test, its administration or action 

upon the results is not designed, intended or used to discriminate. 

(52). 

Employers used this statement to support using any test developed by a 

professional, as long as there was no intent to exclude minorities. In 

t966, the Equal Employment Opportunity Commission (EEOC) adopted guidelines 

that stated that the employer's intent was irrelevant if exclusion of 

minorities was the net effect of using certain tests. The EEOC guideline~ 

declared a test unlawful for use in employee selection unless it predicted 

performance on the job. In t965 the Department of Labor adopted the EEOC 

guidelines. In subsequent years the EEOC and Department of Labor expanded 

the guidelines to include all selection procedures as well as tests. 

In t97t, the Supreme Court ruled in the "Griggs v. Duke Power Co." 

case that employer practices that systematically eliminated minorities were 

illegal unless the practices could be justified by ''business necessity." 

Congress confirmed this view in a t972 amendment to Title VII. During the 

early t970's, various government agencies (the Department of Justice and the 

CSC) developed other guidelines. By t976 two separate sets of guidelines 

were in existence. In t977, the Carter administration authorized an effort 

to unify the two guidelines. In t978, the EEOC, CSC, Department of Labor, 

and Department of Justice adopted the Uniform Guidelines on Employee 

Selection Procedures (52). 

The t978 Uniform Guidelines (52) state that "employer policies or 

practices which have an adverse impact on employee opportunities of any 

race, sex, or ethnic group are illegal under Title VII and Executive Order 

unless justified by business necessity." The guidelines go further in 

defining adverse impact as a selection policy where the selection proportion 

for any race, sex, or ethnic group is less than 80 percent of any other 

race, sex, or ethnic group. Business necessity is defined as a properly 

performed validation study. The validation procedures must be a statistical 

study. Expert or professional opinion or expert/professional development of 

tests according to the guidelines, is not acceptable in lieu of a proper 

statistical study (52). 

While the t978 guidelines answered several important questions about 

discriminatory selection practices, they raised other questions specifically 

related to ATCS selection procedures, which would have to be taken into 

account in current efforts to devise a revised battery of the ATC aptitude 

tests (5). A pertinent feature of these efforts is the fact that data on 

new tests are derived for the most part from new ATCS trainees, a population 

that has already passed screening hurdles. In response to one of these 

questions, Boone and Lewis (7) developed a new procedure to make maximum use 

46 
of available information when correcting validity coefficients for 

restriction in range due to selection. This new procedure was to be 

employed as a more accurate method of correcting spuriously low correlations 

between selection tests given to persons already selected for ATCS training 

(see 5) and ATCS job success. By means of Monte Carlo methods, the 

procedure was compared to the well-known Gulliksen and Thorndike procedures 

and was found in general to be a more accurate correction than Gulliksen'~ 

or Thorndike's methods, especially when restriction is extreme (7). 

To assess the impact of another condition of the Uniform Guidelines, 

viz, test fairness to racial, ethnic, and sex groups, Lewis (34) used Monte 

Carlo data containing characteristics similar to those in current ATCS 

selection data to compare three well-known models of fairness~ (i) 

Thorndike's Constant Ratio Model, (ii) Darlington's Conditional Probability 

Model, and (iii) Einhorn and Bass' Equal Probability Model. The models were 

compared for their robustness to sample size differences, different 

predictor and criterion correlations, and different selection and success 

ratios. Essentially, the study demonstrated that the models were equally 

fair under certain specified conditions and the application of the models 

depended on the goals and aims of the agency involved (34). Lewis 

emphasized the modification of minority recruitment practices as an 

effective means of complying with the Uniform Guidelines without 

necessitating the development of new selection devices. 

In another study stimulated by the Uniform Guidelines (52) and the 

current efforts to develop a new ATC aptitude screening battery (5), the 

effect of recruitment procedures on correcting validity coefficients for 

restriction in range was examined by Boone and Lewis (S). The study 

demonstrated that recruitment procedures can result in widely varying 

unrestricted variances in applicant groups. Several examples were given. 

The effects of these variations in applicant group variance on the 

correction for restriction in range were reviewed with Monte Carlo methods. 

Changing the selection ratio from t.S to 3.0 resulted in a change of the 

estimated unrestricted validity coefficient from .605 to .755. 

Recommendations were offered in the study to help minimize this problem. 

Boone (3), in a report responding to an expressed need from the FAA Office 

of Aviation Medicine, delineated a mathematical procedure for eliminating 

outlier data (experimental aptitude test scores) which have a small 

probability of belonging to the remaining group of data under study. 

Mathematical derivations for the procedures were also presented. Basically, 

the process assumes a multivariate normal distribution and uses the 

Maholanobis D2 distance function to determine the probability that a 

particular data vector belongs to the remaining group of data. ~xamples of 

how to apply the procedure to experimental test batteries for ATCS selection 

were given (3). 

Summary. During the t970's, new administrative and legal standards 

(that resulted from the adoption of the Uniform ~uidelines on Employee 

Selection and from related court decisions) for selection programs coincided 

with a new ATCS pass/fail training program at the Academy and an accelerated 

47 
effort to develop a new ATCS selection battery. These legal changes created 

special statistical and methodological problems for CAMI researchers that 

were basic to addressing issues of the validity and fairness of the ATCS 

selection system. In the last half of the decade, CAMI researchers (i) 

developed new statistical procedures for correcting validity coefficients; 

(ii) studied the effect of recruitment practices on validity studies and 

examined methods for minimizing such effects; (iii) compared several 

statistical models of fairness to determine which is most appropriate under 

what conditions; and (iv) developed a statistical procedure for eliminating 

outlier data in selection test research. The products of these efforts are 

currently being used in continuing validation research at C~~I. 

48 
REFERENCES 

t. Air Traffic Controller Career Committee: The Career of the Atr Traffic 

Controller--A Course of Action. Executive Summary of the Report of the 

Air Traffic Controller Career Committee. Federal Aviation 

Administration, Washington, D.C., January l970. 

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Background Questionnaires as Supplementary Non-Cognitive Measures for 

Use in the Selection of Student Naval Aviators, AEROSPACE MEDICINE, 

42:tl78-tl8l, l97t. 

3. Boone, J. 0.: A Statistical Procedure for Eliminating Extreme, 

Deviant Scores From the Longitudinal Air Traffic Control Data Base. In 

J. 0. Boone and M. A. Lewis: Th~ Selection of Air Traffic Control 

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Report No. AM-79-2l, 1979. 

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Restriction in Range. In J. 0. Boone and M. A. Lewis: The 

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TESTING ASSOCIATION, l: 906-9\ 8, t 97 8.) 

49 
3. Brokaw, L. D.: School and Job Validation of Selection Measures for 

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35:l0t9~t027, l964.) 

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No. ~-ll-36, l97t. 

• 50 
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A Comparative Study of 

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22. Cobb, B. B., and P. L. Nelson: Aircraft-Pilot and other 

Pre-Employment Experience as Factors in the Selection of Air Traffic 

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AM-74-8, t974. 

23. Cobb, B. B., P. L. Nelson, and J, J, Mathews: The Relationships 

of Age and ATC Experience to Job Performance Ratings of Terminal Area 

Traffic Controllers. FAA Office of Aviation Medicine lteport No. 

AM-73-7, t973. (Also published in AEROSPACE MEDIGINE, 45:56-60, t974.) 

24. Cobb, B. B., C. L. Young, and B. L. Rizzuti: Education as a 

Factor in the Selection of Air Traffic Controller Trainees. FAA Office 

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25. Colmen, J, G.: Review and Evaluation of Present Systems for Selection 

of Air Traffic Controllers. Report of Phase t, Task t. Education and 

Public Affairs, FAA Contract No. DOT-FA70WA-237t, Washington, D.C., 

July t970. 

26. Colmen, J, G., and J, Marshall-Mies: Selection of Air Traffic 

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and Public Affairs, Washington, D.C., January t975. 

27. Colmen, J, G., and J, Marshall-Mies: Selection of Air Traffic 

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Education and Public Affairs, Washington, D.C., January t975. 

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29. FAA Office of Personnel: ATCs Intake Study, t97t. 

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PSYCHOLOGY, 5t:ttt-tt9, t967. 

51 
32. Guilford, J. P., and J. I. Lacey, Ed.: ?rinted Classification 

Tests. Report 5, Army Air Forces Aviation Psychology Program Research 

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Office, Washington, D.C., l9l7. 

33. Katzell, M. E.: Expectations and Dropouts in Schools of Nursing, 

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34. Lewis, M. 

Fairness. 

A.: A Comparison of Three Models for Determining Test 

FAA Office of Aviation Medicine ~eport No. AM-79-3, t979. 

35. Lewis, M. A.: Use of the Occupational Knowledge Test to Assign Extra 

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Medicine Report No. AM-78-7, l978. (Also published in AVIATION, 

SPACE, AND ENVIRONMENTAL MEDICINE, 49: tt55...;U59, l978.) 

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37. Marshall-Mies, J., J. G. Colmen, and 0. Domenech: Predicting 

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in the Air Traffic Service. Education and Public Affairs, FAA Contract 

DOT-FA75WA-3546, Washington, D.C., t977. 

38. Mathews, J. J., B. B. Cobb, and w. E. Collins: Attitudes on En 

Route Air Traffic Control Training and Work: A Comparison of Recruits 

Initially Trained at the F~~ Academy and Recruits Initially Trained at 

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39. Mathews, J. J., w. E. Collins, and B. B. Cobb: A Sex Comparison 

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published in PERSONNEL PSYCHOLOGY, 27:535-54t, t974.) 

40. Mathews, J. J., w. E. Collins, and B. B. Cobb: Job-Related 

Attitudes of Non-Journeyman FAA ~ir Traffic Controllers and Former 

Controllers: A Sex Comparison. FAA Office of Aviation Medicine Report 

No. AM-74-7, l974. 

4t. Milne, A. M., and J. G. Colmen: Selection of Air Traffic 

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Affairs, Washington, D.C., l972. 

42. Peterson, P. B., and G. L. Lippitt: Comparison of Behavioral Styles 

Between Entering and Graduating Students in Officer Candidate School, 

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52 
43. Pickrel, E. W.: Development of Occupational Knowledge Tests for En 

Route, Terminal, and Flight Service Station Air Traffic Control 

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l977. (Cited in reference 37.) 

~4. Saleh, S. D., R. J. Lee, and E. P. Brien: Why Nurses Leave Their 

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4S. Sullivan, E. T., W. w. Clark, and E. W. Tiegs: Manual for 

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in AEROSPACE MEDICINE, 32: l H 2-ll t 8, l96t.) 

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(Also published 

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of Training-Entry Age With Intellectual and Personality Characteristics 

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49. Trites, D. K., and B. B. Cobb: Problems in Air Traffic Management: 

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No. 63-31., l963. (Also published in AEROSPACE MEDICI~ 3S:428-436, 

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52. Uniform Guidelines on Employee Selection Procedures: Federal Register, 

Volume 43, No. 166:38290, August 25, 1978. 

53