Carolyn Dollar

Dana Broach 

David J. Schroeder

Civil Aerospace Medical Institute

Federal Aviation Administration

Oklahoma City, OK 73125

October 2003

Final Report

This document is available to the public

through the National Technical Information

Service, Springfi eld, Virginia 22161.

Offi ce of Aerospace Medicine

Washington, DC 20591

Personality Characteristics 

of Air Traffi c Control 

Specialists as Predictors of 

Disability Retirement

DOT/FAA/AM-03/14
NOTICE

This document is disseminated under the sponsorship of

the U.S. Department of Transportation in the interest of

information exchange. The United States Government

assumes no liability for the contents thereof.
i

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1

PERSONALITY CHARACTERISTICS OF AIR TRAFFIC CONTROL SPECIALISTS

AS PREDICTORS OF DISABILITY RETIREMENT

INTRODUCTION

The number of U. S. workers leaving employment for 

reasons of disability has increased over the past decade. 

Between 1990 and 1999, the number of persons receiving 

Social Security disability benefi ts grew from 3,011,000 

to 4,879,000 (U. S. Census Bureau, 2001). During the 

same years, 54,359 civilian government employees took 

disability retirements (OPM, 2002), representing 12.5% 

of all civilian retirements from the federal workforce. 

Because disability has an obvious adverse impact on the 

retiree and increases costs to employers in monetary 

monthly payouts and medical benefi ts, recent literature 

has focused on measures to better understand the factors 

involved in disability retirements.

Review of Recent Research to Understand Factors 

Involved in Disability Retirements

Previous research has focused on worker’s compensation claims and psychological factors (see, for examples, 

Hui, Arvey, Butler, & Nutting, 2001; Butcher & Harlow, 

1987). As worker’s compensation claims may precede a 

disability retirement, researchers have hypothesized that 

psychological factors (e.g., personality) may also be related 

to disability retirement. Rosen, Frymoyer and Clements 

(1980) found that the Hypochondriasis and Hysteria 

scales from the Minnesota Multiphasic Personality Inventory (MMPI) were signifi cant predictors of disability in 

patients with lower back pain. 

Fore (1998) found that two psychological scales, 

Locus of Control Scale (LOC) and the Safety Locus 

of Control (SLOC), predicted on-the-job injuries. The 

LOC was also a signifi cant predictor of whether or not 

an injured worker fi led a claim for worker’s compensation. Krause et al. (1997) found that a variety of factors 

were signifi cantly associated with disability retirements. 

These included among others: (1) physical factors such 

as heaviness of workload; (2) environmental infl uences 

such as having to work in an uncomfortable position for 

an extended period of time; and (3) psychological aspects 

such as mental strain or job dissatisfaction. Furthermore, 

Haldorsen, Indahl, and Ursin (1998) studied employees 

for whom interventions had been taken to correct low 

back pain. A discriminant analysis of scores from several 

psychological tests resulted in correctly classifying 72% of 

the nonreturners versus returners to work. The dominant 

factor in determining group membership in that analysis 

was the Internal Health Locus of Control measure. A 

subsequent discriminant analysis in the same study using 

medical, work ability, psychological, and other variables 

resulted in a correct classifi cation of 77% of the members, 

and the same locus of control measure continued to be 

a major contributor.

In an exploration of early retirements among male ambulance personnel versus other health care staff, Rodgers 

(1998) found musculoskeletal, circulatory, and mental 

disorders (a large proportion of which were related to 

alcohol problems) to be the chief causal factors. Thus, 

even with studies in which physical disability was the 

primary focus, scientists in several countries have employed a variety of psychological tests to investigate the 

role of those factors in on-the-job injuries, workman’s 

compensation claims, and eventual claims for disability 

retirement.

There are several reasons that the current study was 

conducted. First, as with all federal agencies, the Federal 

Aviation Administration (FAA) has recently been tasked 

with becoming more effi cient with Congressional funding. Second, about one-third of the agency’s employees 

are air traffi c control specialists (ATCSs), who represent 

comparatively high costs in training until they reach a 

fully profi cient performance level. Finally, disability retirement under the federal system can only occur when an 

agency has exhausted all reasonable attempts to retain that 

employee in a productive capacity through accommodation or re-assignment. Since the ATCS occupation is one 

that requires special skills, opportunities for job transfers 

are limited. Hence, it would be fi nancially benefi cial for 

the agency to identify factors related to ATCS disabilities 

so that interventions might be designed to reduce those 

kinds of retirements. 

The FAA has used Cattell’s 16 Personality Factor Test 

(“16PF,” 1949) as part of the medical exam for individuals entering the agency as ATCSs since the early 1960s. 

Historically, the test (Forms A and B) was fi rst used to 

identify/protect controllers who might experience “burn 

out” or other stress effects later in their careers (Holbrook, 

1974). Eventually it was used as a screen to help the agency 

locate potential employees with profi les requiring a more 

in-depth psychological evaluation (Convey, 1984). 

Scores on the 16PF were used in this study to determine 

personality characteristics that might be associated with 

disability retirements from the controller workforce. In 

view of the stability asserted for personality traits (Costa & 

McCrae, 1980; Soldz & Vaillant, 1999) and the previous 

research, we hypothesized that personality traits measured 
2

at entry into the ATCS occupation might differentiate 

between controllers that leave the occupation on the basis 

of a disability retirement and those that remain active and 

employed in the occupation.

METHOD

Sample

A search of data extracted from the FAA’s Consolidated 

Personnel Management Information System (CPMIS) 

identifi ed records for 55 disability retirees from the terminal and en route ATCS workforce between October 

1995 and September 2001. These cases were matched 

with records for currently active controllers on: (a) age 

at entry; (b) gender; (c) race; (d) air traffi c option; and 

(e) scores on the competitive OPM ATCS aptitude test 

battery (TMC). Three disabled subjects were eventually 

excluded due to missing data, resulting in a sample of 52 

disability retirees and 104 active controllers.

Cases and controls were matched fi rst on age, gender, 

race, and option, then on aptitude. Because of the variability in TMC scores, just over half of the disability 

retirees were matched exactly on TMC by two control 

cases. When an identical TMC score could not be found, 

control subjects were drawn randomly from a pool with 

scores within about ±5 points on a 70 to 100 point 

scale. As indicated before, Cattell’s 16PF test had been 

collected for the subjects and controls as part of the prehire medical examination. Thus, the 16PF scores were 

available for all subjects who were retained in the study. 

On average, the 16PF had been administered 12 years 

prior to the year of the disability retirement (range 6 to 

24 years) for the cases in the study. Characteristics of the 

controllers in the active and disability retiree groups are 

shown in Table 1.

Measures/procedure

As already stated, Cattell’s 16 PF has been administered 

as a pre-screen for ATCS candidates for over 30 years. 

Each of the two forms (A and B) of the test is comprised 

of 187 items that have two opposite response choices (i.e., 

“always” or “never”) and a “neutral” choice (i.e., “sometimes”). Scale scores were computed from item responses 

and converted into sten scores in accordance with Cattell, 

Eber, and Tatsuoka, (1970). Appendix A provides a brief 

description of the 16 factors and characteristics of persons 

with either low or high scores on each factor. A stepwise 

multivariate discriminant analysis was performed using 

SPSS version 10.0 (SPSS, 2002) on the data.

RESULTS

Descriptive Statistics

Table 1 shows that the TMC scores were highly 

similar (M=91.9, SD=4.9 versus 91.7, SD=4.9) for the 

disability retirees, compared with the non-disabled group 

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 respectively. Not shown, the retirement age (37 versus 49) 

and length of tenure before leaving (12 versus 17 years) 

for the disabled ATCSs were both much lower than that 

for the average federal disability retiree (OPM, 2002). 

This was expected, however, since ATCS employees are 

younger on average than most other federal occupations 

and retire with disabilities earlier than the non-controller 

FAA workforce (Holbrook, 1974). Figure 1 shows the 

mean sten scores on each of the 16 factors for the active 

ATCSs versus the disability retirement group.

Visual inspection of the means and the graphed 16PF 

data suggested that there were no remarkable differences 

between the groups. (See Figure 1). The goal of our analysis 

was to determine which personality factors distinguished 

between active and disabled subjects. Therefore, univariate tests for differences, factor by factor, were not appropriate. Instead, multivariate discriminant analysis was 

employed to determine the unique contribution of each 

personality factor and to construct a statistical function 

for distinguishing between groups.

Discriminant Analysis

Results of the stepwise discriminant analyses showed 

that the best predictor variables of group membership 

were Sensitivity (I), Suspiciousness (L), and Tension 

(Q4). However, these three variables accounted for only 

about 20% of the variance (Wilk’sΛ = .807, χ2(3) = 32.8, 

p < .001). Overall, 69.2% of the cases were correctly 

classifi ed. The function coeffi cients that were generated 

by the analysis are shown in Table 2. The discriminant 

function was:

D = -8.10 + .386 (I-Sten) - .313 (L_Sten) + .340 (Q4_Sten),

indicating that disabled ATCSs are less suspicious 

but more sensitive and tense than those in the 

control group.

DISCUSSION

This study replicates the fi ndings of previous research 

in that psychological factors may be helpful in predicting negative work-related outcomes such as disability 

retirement. For example, personality and locus-of-control 

measures have been shown to differentiate between groups 

with and without negative work-related health outcomes 

(Fore, 1998). Similar levels of predictability were found 

across the current study and the Haldorsen et al. 1998 

study (over 69% of the ATCSs, compared to from 72% 

to 77% of subjects in the latter study, respectively, were 

correctly classifi ed). As in the Krause et al. 1997 study, 

information in this study was collected prior to the onset 

of the disability. However, the current study was unique 

in that the data were gathered prior to the ATCSs entry 

on duty. 

Controllers on disability retirement, when compared 

with active controllers, were found to be less suspicious, 

more sensitive and insecure, and generally more tense and 

frustrated. A diffi culty in interpreting these fi ndings is 

that while the average score on the tension measure for 

the disability retirees revealed greater tension than that 

of the active controllers, the average was still below that 

of the normative group on the 16PF. For the other two 

personality dimensions, Sensitivity and Suspiciousness, 

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disability retirees were in the average range. Thus, while 

the comparisons reveal a difference on certain personality 

dimensions for active controllers versus disability retirees, 

the overall profi le for the group of disability retirees was 

comparable to that of other individuals entering into the 

ATCS profession. They evidenced an above- average level 

of intelligence; high self-reported emotional stability and 

self-suffi ciency; and were generally venturesome, assertive, and conscientious. These fi ndings suggest that upon 

entry on duty as an ATCS, the disability retirees present 

themselves, on the basis of their responses to the 16PF, 

in ways that are similar to that of other controllers. 

The magnitude of the effects of psychological factors 

in the current study suggests that other factors may play 

a more prominent role in shorter job tenure. Stressors 

such as the tasks inherent in the job itself, variable work 

shifts, other job-related factors, or the match between the 

individual abilities and the demands of the job might very 

well contribute more reliably toward the identifi cation 

of persons who leave employment with disability retirements. In addition, there are indicators that experiences 

outside the work environment contribute to how people 

feel about their work. Thus, we need to enlarge our search 

to identify the other situational, interactive and both 

work and non-work-related factors that may contribute 

more substantially to the incidence of medically disabling 

conditions within the ATCS workforce.

REFERENCES

Butcher, J.N. & Harlow, T.C. (1987). Personality assessment in personal injury cases. In I.B. Weiner 

& A.K. Hess (Eds.) Handbook of forensic psychology

(pp. 128–54). New York: Wiley.

Cattell, RB. (1949). The Sixteen P.F. Questionnaire (1st

ed.). Champaign, IL: Institute for Personality and 

Ability Testing, Champaign, IL.

Cattell, R., Eber, H. and Tatsuoka, M. (1970). Handbook 

for the Sixteen P.F. Questionnaire (1st ed.). Institute for ed.).Institutefor st

Personality and Ability Testing, Champaign, IL.

Convey, J.J. (1984). Personality assessment of ATC applicants. In S.B. Sells, J.T. Dailey, and G.W. Pickrell (Eds.) Selection of Air Traffi c Controllers, 1984. 

(DOT/FAA/(DOT/FAA/AM-84/2). Washington, 

DC: Federal Aviation Administration Offi ce of 

Aviation Medicine.1

Costa, P.T. Jr., & McCrae, R.R. (1980). Still stable after 

all these years: Personality as a key to some issues in 

adulthood and old age. In P.B. Baltes & O.G. Brim, 

Jr. (Eds.) Life span development and behavior (Vol. 

3, pp. 65–102). New York: Academic Press.

Fore, T.A. (1998). Predicting workers’ compensation 

claims and on-the-job injuries using four psychological measures. (Doctoral dissertation, University 

of North Texas, 1998). UMI number 9841419. Dissertation Abstracts International, 59 (7A), 2601.

Holbrook, H., (1974). Civil Aviation Medicine in the 

Bureaucracy, Bethesda, Maryland.

Haldorsen, E., Indahl, A., and Ursin, H, (1998). Patients 

with low back pain not returning to work. Spine,

23(11), 1202-8.

Hui, L., Arvey, R.D., Butler, R.J., & Nutting, S.M. 

(2001). Correlates of work injury frequency and 

duration among fi refi ghters. Journal of Occupational 

Health Psychology, 6, 229–42.

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1

This publication and all Offi ce of Aerospace Medicine technical 

reports are available in full-text from the Civil Aerospace Medical 

Institute’s publications Web site: http://www.cami.jccbi.gov/aam400A/index.html
5

Krause, N., Lynch, J., Kaplan, G., Cohen, R.D., Goldberg, D.E., and Salonen, J.T. (1997). Predictors of 

disability retirement. Scandinavian Journal of Work 

Environment Health; 23, 403-13.

Offi ce of Personnel Management (2002). Retirement 

Statistics. Washington, DC: Author.

Rodgers, L. (1998). A fi ve-year study comparing early 

retirements on medical grounds in ambulance personnel with those in other groups of health service 

staff. Part II: Causes of retirements. Occupational 

Medicine;48(2) 119-32.

Rosen, J., Frymoyer, J. Clements, J. (1980). A further 

look at validity of the MMPI with low back patients. 

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(Ed.) Recovery of the FAA Air Specialist Workforce, 

1981-1992. (DOT/FAA/AM-98/23). Washington, 

DC: Federal Aviation Administration Offi ce of 

Aviation Medicine.1

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traits and the life course: A 45-year longitudinal 

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208–32.

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161-70.

A1

APPENDIX A

FACTOR A (WARMTH)

LOW SCORE HIGH SCORE

RESERVED, DETACHED, FORMAL OUTGOING, WARMHEARTED

CRITICAL, RIGID EASYGOING, LIKES PEOPLE

COOL, ALOOF PARTICIPATING, ADAPTABLE

FACTOR B (INTELLIGENCE)

LOW SCORE HIGH SCORE

LESS INTELLIGENT MORE INTELLIGENT, BRIGHT

CONCRETE THINKING ABSTRACT THINKING

FACTOR C (EMOTIONAL STABILITY)

LOW SCORE HIGH SCORE

AFFECTED BY FEELINGS EMOTIONALLY STABLE

EMOTIONALLY LESS STABLE FACES REALITY

EASILY UPSET CALM, UNRUFFLED

WORRYING MATURE

FACTOR E (DOMINANCE)

LOW SCORE HIGH SCORE

HUMBLE ASSERTIVE

MILD AGGRESSIVE

ACCOMMODATING, CONFORMING STUBBORN, HEADSTRONG

EASILY LED, OBEDIENT COMPETITIVE

SUBMISSIVE BOSSY, DOMINANT

FACTOR F (IMPULSIVITY)

LOW SCORE HIGH SCORE

SOBER, SERIOUS HAPPY-GO-LUCKY

PRUDENT, RESTRAINED IMPULSIVELY LIVELY

TACITURN ENTHUSIASTIC

SILENT, INTROSPECTIVE EXPRESSIVE, TALKATIVE

FACTOR G (CONFORMITY)

LOW SCORE HIGH SCORE

EXPEDIENT, UNDEPENDABLE CONSCIENTIOUS, RULE BOUND

DISREGARDS RULES PERSEVERING

FEELS FEW OBLIGATIONS STAID

SELF-INDULGENT MORALISTIC

FACTOR H (BOLDNESS)

LOW SCORE HIGH SCORE

SHY, TIMID VENTURESOME, UNINHIBITED

RESTRAINED SOCIALLY BOLD

THREAT-SENSITIVE SPONTANEOUS

HESITANT RESPONSIVE

FACTOR I (SENSITIVITY)

LOW SCORE HIGH SCORE

TOUGH-MINDED TENDER-MINDED

SELF-RELIANT CLINGING, INSECURE

REALISTIC OVER-PROTECTED

NO-NONSENSE SENSITIVE

HARD KINDLY, GENTLE

FACTOR L (SUSPICIOUSNESS)

LOW SCORE HIGH SCORE

TRUSTING SUSPICIOUS

ADAPTABLE SELF-OPINIONATED

FREE OF JEALOUSY HARD TO FOOL

EASY TO GET ALONG WITH SKEPTICAL

PLIANT TO CHANGES DISTRUSTFUL
A2

APPENDIX A (CONTINUED)

FACTOR M (IMAGINATION)

LOW SCORE HIGH SCORE

PRACTICAL, IMAGINATIVE, BOHEMIAN

CONVENTIONAL WRAPPED UP IN URGENCIES

REGULATED BY EXTERNAL REALITIES CARELESS OF PRACTICAL 

CAREFUL MATTERS

DOWN-TO-EARTH” CONCERNS ABSENT-MINDED

PROPER UNCONVENTIONAL

FACTOR N (SHREWDNESS)

LOW SCORE HIGH SCORE

FORTHRIGHT SHREWD

NATURAL, ARTLESS CALCULATING

UNPRETENTIOUS, GENUINE WORLDLY

OPEN PENETRATING

SPONTANEOUS SOCIALLY AWARE

POLISHED

FACTOR O (INSECURITY)

LOW SCORE HIGH SCORE

SELF-ASSURED APPREHENSIVE

CONFIDENT SELF-REPROACHING

SERENE, COMPLACENT WORRYING

FREE OF GUILT TROUBLED, LONELY

SECURE BROODING

GUILT-PRONE

FACTOR Q1 (RADICALISM)

LOW SCORE HIGH SCORE

CONSERVATIVE EXPERIMENTING

RESPECTING ESTABLISHED IDEAS LIBERAL

TOLERANT OF TRADITIONAL ANALYTICAL

 DIFFICULTIES FREE-THINKING

REBELLIOUS

OPEN TO CHANGE

FACTOR Q2 (SELF-SUFFICIENCY)

LOW SCORE HIGH SCORE

GROUP-DEPENDENT SELF-SUFFICIENT

A “JOINER” AND SOUND FOLLOWER PREFERS OWN DECISIONS

LISTENS TO OTHERS RESOURCEFUL

FACTOR Q3 (SELF-DISCIPLINE)

LOW SCORE HIGH SCORE

UNDISCIPLINED SELF-CONFLICT CONTROLLED

FOLLOWS OWN URGES FOLLOWING SELF-IMAGE

CARELESS OF PROTOCOL, LAX COMPULSIVE

UNCONTROLLED SOCIALLY PRECISE

FACTOR Q4 (TENSION)

LOW SCORE HIGH SCORE

RELAXED, TRANQUIL TENSE, OVERWROUGHT

UNFRUSTRATED FRUSTRATED, FRETFUL

COMPOSED DRIVEN

Descriptive information for the factors was taken from the 16PF test profi le 

(1967),Karson and O’Dell (1976), and the Administrator’s manual for the 16PF 

(1986).