lated A-Trait records required a cutting score of
35, but this resulted in the misclassification of
144 (52.9%) of the authentic records,

While the procedure using raw scores may
serve as an effective screen in a “normal” popu-
lation, a perusal of the norms for the STAI®
indicates that the false-positive rate is likely to
be quite high if this approach is applied to other
populations. For example, use of 48 as the cut-
ting score for the A-State scale would result in
false-positive rates of 52% for neuropsychiatric
patients, 44% for prison inmates, and 36% for
medical/surgical patients. Therefore, the records
of the experimental groups, as well as 125 records
from Spielberger’s neuropsychiatric patient nor-
mative sample were subjected to further analysis.
The neuropsychiatric sample was selected for
analysis since this was the normative group with
the highest mean A-State and A-Trait scores.
The analysis consisted of the determination of
the number of Ss in each condition using each

of the four possible ratings for each item. It
was found that ratings indicating the lowest level
of anxiety (responses which added only one point
to §’s score) were relatively common among
authentic and patient records, but were infre-
quent in stress-simulated protocols. An index
was then developed using those specific items
that were given “one” (lowest anxiety) ratings
on no more than’ 10 stress-simulated records.
Each set of STATI records (authentic, stress-
simulated, and patient) was then divided in half
on an odd-even basis. The number of “one”
ratings on the 12 A-State and 5 A-Trait items
selected for analysis in each record was deter-
mined. It was found that among records with
high scores (48 or more on A-State), a combina-
tion of six A-State items (numbers 1, 2, 3, 10, 11,
12) and two A-Trait items (numbers 21 and 30)
provided the best differentiation between authen-
tic and patient records on the one hand, and
stress-simulated records on the other. If any

TABLE 2.—A-State and A-Trait cumulative raw score distributions for authentic and two types of stress-simulated records,

A-State A-Trait

Score Concealed — Sum Concealed — Sum
Authentic Simulated Simulation Correct” Authentic Simulated Simulation Correct*
(N=272) (N=126) (N=146) (N=544) (N=272) (N=126) (N=146) (N=6544)

65 or more 0 93 48 413 0 70 25 367

0 97 52 421 0 17 35 384

0 101 62 435 0 80 39 391

0 103 72 4aT 1 84 42 397

1 104 78 453 4 85 55 408

2 108 89 467 4 87 64 419

2 109 96 475 6 90 7 427

2 110 104 484 6 93 78 437

2 110 106 486 6 95 85 446

4 112 112 492 7 97 92 454

5 114 113 494 9 97 93 453

6 116 117 499 10 98 101 461

7 118 119 502 12 99 105 464

7 119 123 507 15 100 ill 468

8 119 126 509 17 100 115 470

10 119 131 512 18 103 118 475

10 119 133 514 20 104 120 476

12 120 135 515 21 106 124 481

16 120 136 512 24 110 125 483

19 120 137 510 30 112 126 480

21 120 139 510 38 115 127 476

26 120 139 506 44 115 129 472

32 121 139 500 52 117 130 467

39 121 140 494 87 117 134 466

43 122 141 492 68 117 135 457

55 125 141 483 78 118 135 a7

*Number of records correctly classified if all scores at or above that level are designated as biased.





‘Tanue 1.—Mean A-State and A-Trait raw scores for authentic STATI records (first administration) and STAI records
simulated for stress under bias and concealed-bias instructions (second administration).

A-State A-Trait
Group
Authentic Simulated t Authentic Simulated t
Stress Bias__._.------- 34,02 69.78 33, 13*** 34.90 63.73 20. 46***
Concealed Stress Bias..- 34,88 60.01 31. 80*** 36. 52 56.08 22. 01***
te. --- 0.95 12, 62*** 1.60 5. 29%**

ee D <.001

IIL. Results.

As expected, there were large differences be-
tween STAI scores obtained under normal con-
ditions and those obtained following the re-
sponse-bias instructions (Table 1). Both of the
stress instruction groups obtained higher mean
A-State and A-Trait scores on the stress-simu-
lated STAI administration than on the form
taken with standard instructions. The stress-
simulated scores were somewhat higher for the
group given the simpler instructions than for the
group given explicit instructions to conceal their
attempts to bias the records, It was also ap-
parent in comparing the scores of the biased
A-State and A-Trait scales that the A-State
measure increased more than the A-Trait meas-
ure when respondents attempted to exaggerate
stress, ¢ (270) =10.02, p<.001.

There were no significant differences between
males and females on the A-State or A-Trait
scales under either the standard or simulated
conditions. Therefore, all subsequent analyses
were conducted without respect to the sex of the
respondent.

For each item, the percentage of Ss who indi-
cated higher anxiety on the second than on the
first rating was determined for the entire group
of Ss. For items on the A-State scale, the mean
percentage of Ss showing increased anxiety per
item on the second administration was 80.17
(S.D.=6.25), while for items on the A-Trait
scale, the mean percentage was 73.06 (S.D.=8.99).
The percentages for specific items on the A-State
scale ranged from 60.0 to 87.9; the range for
items on the A-Trait scale was 59.8 to 85.0.

Since the effects of bias were rather uniform
across items, it was felt that the total raw scores
for the STAI scales might serve as well as any
sub-group of items in discriminating between
authentic and stress-simulated records. It was

found that using scores from the A-State scale
alone provided the best index of response bias
after considering the scores from the two scales
separately and summed together. The distribu-
tion of the scores indicated that the most efficient
classification of records resulted when raw scores
of 48 or more were considered “stress-simulated”
(Table 2). The overall hit rate using this score
was 515 correct profile classifications out of 544
records (94.7%). This score included only 12 of
the 272 (4.4%) authentic records (false posi-
tives) while 255 of the 272 (93.8%) stress-
simulated scores were correctly identified. Of
the biased records, 120 of the 126 (95.2%) records
from the group simply instructed to exaggerate
stress and 135 of the 146 (92.5%) records from
the Ss who tried to conceal the stress-simulation
were correctly classified as simulations. The
difference between the proportions of correct
classifications for the two groups given different
stress-simulation instructions was not significant,
and substantial differences were not apparent
except toward the upper limit of the distribution
of scores. (This was also true of subsequent
analyses; therefore, all remaining findings are
presented for the pooled instruction groups.)
To identify 95% of the stress-simulated records
required a cutting score of 45 which resulted in
a false-positive rate of 7.7%.

Use of the raw scores for discriminating be-
tween stress-simulated and authentic A-Trait
records was not as successful as was the case
with the A-State scale; however, it was possible
to achieve a reasonable hit rate using 47 as the
cutting score (Table 2). This resulted in the
correct classification of 483 of 544 profiles
(88.8%). Of the 272 stress-simulated records,
235 (86.4%) were included by this score, while
24 of 272 (8.8%) authentic records were mis-
classified. To identify 95% of the stress-simu-


record contained two or more “one” ratings
among these eight items, it was then classified as
authentic, and the remaining protocols were then
screened for stress-simulation by the raw score
procedure previously described. Using this two-
step procedure resulted in a reduction of six in
the number of patient records misclassified as
biased and a reduction of two in the number of
misclassified authentic records. None of the
classifications of simulated records in this half
of the sample was changed by this procedure.
When applied to the other half of each set of
STAI records, it was found that seven patient,
two authentic, and two stress-simulated records
were removed from that group of records classi-
fied as biased by use of the cutting score of 48.
Thus, considering the entire sample together, the
number of authentic records misclassified was
reduced from 12 to 8 (2.9%), the number of
patient profiles classified as biased was reduced
from 61 (48.8%) to 48 (38.4%), while the num-
ber of stress-simulated records correctly identi-
fied decreased from 255 to 253 (93.0%).

If only A-State scores are combined, the six
A-State items serve most effectively for the first
step in the screening process. Applied to all
A-State records, the two-step procedure, again
employing a cutting score of 48, resulted in a
reduction of 11 false-positive classifications in
patient records at the cost of exqluding two cor-
rect classifications of stress-simulated protocols.
There was no effect on authentic records in this
case.

When considering A-Trait scores alone, the
procedure which resulted in the most successful
classification rate for the half-sample split on an
odd-even basis was to classify as “valid” any
A-Trait record which contained a “one” rating
on any of the four items 21, 26, 27, and 30, then
classify the remaining records by the cutting
score of 47. This resulted in a reduction of five
patient and three authentic false-positive classi-
fications at the cost of incorrectly excluding a
single stress-simulated record. For the second
half of the sample, this procedure reduced patient
false-positives by seven, and authentic false-
positives by one, while increasing misclassified
stress-simulated records by one. Considering the
entire sample, the two-step procedure reduced
the number of misclassifications of patient
protocols from 62 (59.6%) to 50 (40.0%), and of
authentic records from 24 to 20 (7.4%). The

reduction in correct identifications of stress-
simulated records was from 235 to 233 (85.7%).

IV. Discussion.

While the findings indicate that STAI scores
are quite susceptible to intentions to exaggerate
stress effects, it is also clear that the STAI user
can screen records for this type of bias with
relatively little effort and with considerable
effectiveness. While the application of this
screening approach to other “normal” populations
may diminish the effectiveness somewhat from
the 95% hit rate attained with the experimental
population, the normative data for “normal”
student groups suggest that at worst the false-
positive rate would probably not exceed 14%
using the raw score alone, and would be less using
the two-step procedure. The overall effectiveness
is also dependent upon the cutting score chosen
by the user; however, it is possible to vary cut-
ting scores across a considerable range to maxi-
mize correct identification of either authentic or
stress-simulated protocols. For example, if the
user can tolerate the loss of legitimate records
required by reduction of the cutting scores, it is
possible to achieve 95% assurance that stress-
simulated records will not be accepted as legiti-
mate.

The question as to the use of the two-step
procedure in preference to the use of the raw
score alone is an open one. The evidence sug-
gests that the impact of using the item screening
prior to application of a cutting score is prob-
ably minimal. Therefore, it seems reasonable to
suggest that the raw-score-only approach be used
unless the user has a particular need for legiti-
mate high-scoring profiles. It should be empha-
sized that as with all such indices, STAI records
classified as stress-simulated can only be consid-
ered as “suspect” since there is relatively little
pasis for discriminating between records reflect-
ing legitimate intense anxiety and records biased
by stress-simulation. Thus, with patients, both
neuropsychiatric and surgical, prison inmates,
and other samples where high anxiety may be
common, the false-positive rate will be quite high
when using this screening procedure. Under
circumstances where the false-positive rate is
high, or where loss of authentic records cannot
be tolerated, the screening procedure might serve
as a “flag” to indicate the need for further eval-
uation of an individual’s affect status.


TECHNICAL REPORT STANDARD TITLE PAGE

1, Report No. 2. Government Accession No. 3. Recipient's Catalog No.
FAA-AM~72=23

4, Title and Subtitle 5. Report Date
A STUDY OF THE STATE-TRAIT ANXIETY INVENTORY AND May 1972
THE ASSESSMENT OF STRESS UNDER SIMULATED 5. Performing Organization Code
CONDITIONS

7. Author(s) 8. Performing Organization Report No.

Roger C. Smith, Ph.D.

9. Performing Organization Name and Address 10. Work Unit No.
FAA Civil Aeromedical Institute
P. O. Box 25082 T1. Contract or Grant No.

Oklahoma City, Oklahoma 73125

13. Type of Report and Period Covered

12. Sponsoring Agency Name and Addres«

Office of Aviation Medicine OAM Report
Federal Aviation Administration
800 Independence Avenue, S.W. 14. Sponsoring Agency Code

Washington, D. C. 20591
15. Supplementary Notes

This research was completed under AM-A-72-PSY-34.

16. Abstract

One approach to the measurement of stress in ATC and other aviation personnel is
through assessment of anxiety. One means of accomplishing this is to use the
State-Trait Anxiety Inventory (STAI), a 40-item self-report technique. However,
the STAI may be susceptible to effects of biasing response sets. In order to
determine if stress can be simulated on the STAI, the responses of 283 subjects
obtained under normal instructions were compared to their responses obtained when
asked to make it appear as if they were experiencing a high degree of stress.

It was found that while both the A-State (current anxiety level) and A-Trait
(anxiety proneness) scales were influenced by this response set, the effect was
greater for the A-State scale. Using the A-State raw score alone as an index of
bias resulted in 95.7% accuracy in protocol classification. A two-step procedure,
using eight items and the A-State raw score, was subsequently devised which
reduced false-positive classifications of legitimate psychiatric patient profiles
from 49% to 38% with no reduction in discriminatory power for "normal" records.
The application of the index to clinical and research settings in aviation was
discussed.

17. Key Words 18. Distribution Statement
Stress Availability is unlimited. Document may
Personnel Assessment be released to the National Technical
Psychological Evaluations Information Service, Springfield, Virginia
Anxiety 22151, for sale to the public.

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages | 22. Price
Unclassified Unclassified 5 $3.00

Form DOT F 1700.7 (2-69)



In comparison to the hit rate for stress-
simulation attained with the STAT, it was found
that the most efficient index for the same stress-
simulation bias in the Composite Mood Adjective
Checklist? achieved 90% accuracy in classification
of simulated and authentic records.? The widely
used # minus X index developed by Gough’ for
detecting simulation of psychopathology on the
MMPI has a maximum overall hit rate of ap-
proximately 86%, with a limit of 88% accuracy
in identifying biased records. Thus, it appears
that the efficiency of the screening procedures
described in this study compares favorably with

the efficiency of indices generally considered
useful for identifying response biases.

In sum, it appears that the STAT can be used
for measuring the anxiety of air traffic control-
lers, or workers in other high-demand occupa-
tions, with considerable confidence that the
validity of findings will not be reduced by the
unsuspected effects of biasing response sets. It
should therefore prove a most useful technique
for both long- and short-term studies of stress in
air traffic controllers where a brief, easily admin-
istered measure of anxiety is desired.

REFERENCES

1. Gough, H. G.: The F Minus K Dissimulation Index
for the MMPI, JOURNAL OF CONSULTING PSY-
CHOLOGY, 14 :408~413, 1940.

2. Malmstrom, E. J.: Composite Mood Adjective Check
List, Unpublished Manuscript, University of Cali-
fornia, Los Angeles, 1968.

3. Smith, R. C.: Assessment of a “Stress” Response-Set
in the Composite Mood Adjective Checklist. FAA
Office of Aviation Medicine Report No. AM~71-14,
1971.

4, Smith, R. C., C. BE. Melton, Jr., and J. M. McKenzie:
Anxiety in Air Traffic Controllers. Paper presented
to the 43rd Annual Scientific Meeting of the Aero-
space Medical Association, Miami, Florida, May 1972.

5. Spielberger, C. D., R. L. Gorsuch, and R. E. Lushene:
Manual for the State-Trait Anwiety Inventory. Palo
Alto, California, Consulting Psychologists Press, Inc.,
1970.





A STUDY OF THE STATE-TRAIT ANXIETY INVENTORY AND THE
ASSESSMENT OF STRESS UNDER SIMULATED CONDITIONS

I. Introduction.

One approach to the measurement of stress in
air traffic control and other aviation personnel is
through the assessment of anxiety. There are a
number of physiological and psychological tech-
niques for accomplishing such measurements;
however, many involve considerable inconven-
ience or discomfort, time, or are not suitable for
repeated administration. One recently developed
technique which may circumvent many of these
problems is the State-Trait Anxiety Inventory
(STAI). This device produces scores indicating
the individual’s current level of anxiety, ie.,
A-State, and how prone the individual is to ex-
perience anxiety, ic, A-Trait. It is easily ad-
ministered and scored and, since it contains only
40 items which are to be rated on four-point
scales, it takes only a few minutes for the re-
spondent to complete. It is also supported by a
substantial normative data-base from a variety
of different populations. For these reasons, it
has already been employed in the study of stress
in air traffic controllers.‘

Although the STAI is a promising inventory
for the measurement of anxiety, it may be sus-
ceptible, as are most self-report techniques, to the
effects of biasing response sets. In particular,
there are situations in which respondents might
tend to elevate the level of anxiety which they
report on the STAT scales. For example, records
obtained from some individuals engaged in pro-
fessions such as law enforcement, air traffic con-
trol work, piloting aircraft, medical surgery, and
the like might be biased by over-emphasis of the
impact of job-related stress upon their affective
states. The purpose of this investigation was
twofold. The first purpose was to determine to

The assistance of Gary Hutto and Charles Abbott in
the conduct of this study is gratefully acknowledged.
The author is also indebted to Charles D. Spielberger
who supplied the psychiatric patient protocols used in
some of the analyses.

what extent STAI scores are influenced by at-
tempts of respondents to emphasize the appear-
ance of stress, The second purpose of the study
was to then establish procedures for identifying
STAI protocols biased by such tendencies,

II. Method.

The STAI was administered twice to each of
283 paid student volunteers (200 males, 83 fe-
males) recruited primarily from the University
of Oklahoma. The first administration of the
STAI was made with the standard instructions
for both the A-State and A-Trait forms. These
instructions request the respondent to rate each
of the 20 A-State items according to their current
feelings and each of the 20 A-Trait items accord-
ing to how they generally feel. Each item is
answered by indicating which of four response
categories best describes to what degree items
such as “I am tense” apply to the respondent.
For A-State items, the categories range from
“not at all” to “very much,” while for A-Trait
items the range is from “almost never” to “almost
always.” The Ss were not told that a second
administration was planned. After completion
of the first STAI, there was a two to three minute
break, then Ss were asked to complete the STAI
a second time. The first 131 Ss were each asked
to respond as would an employee who wanted to
make it appear that he was in an extremely
stressful job, The remaining 152 Ss were given
similar instructions with the addition of a re-
quest to “try to prevent the examiner from know-
ing that you are exaggerating your responses.”
The Ss were without access to their first STAI
records during the second STAI administration.
Five Ss from the first group, and six Ss from the
second group, did not understand the instruc-
tions, or were unable to complete the task as
directed and were subsequently eliminated from
the sample.