HEIGHT AND WEIGHT ERRORS IN AEROMEDICAL
CERTIFICATION DATA

(Introduction

A physician’s comprehensive physical exami-
iation usually includes the measurement of
ieight and weight because of their combined
‘elevance to many conditions of major medical
soncern, An excessive weight gain or loss, or an
ixcessive rate of change in weight per height,
eadily elicits increased diagnostic attention.

On the standard airman medical application
1eight and weight are requested in inches and
rounds, but measurement of these two items at
he time of the aeromedical certification exami-
1ation is not required. These values on the ap-
lication are usually the airman’s stated estimates
nd are therefore vulnerable to all the possible
ypes of errors of stated (unmeasured) data.

Many epidemiology studies have used height
nd weight data to determine the presence and
legree of obesity in relation to coronary heart
lisease (GHD). One such characterization of
besity is the well-known Framingham Relative
Veight Index (FRWI), as formulated by the
Tramingham Heart Study (FHS). This index
3 based on measured values of height and
veight.1. A male whose FRWI is 100.0% has a
veight equal to the median weight of all FHS
aales of his identical height at the 1950 incep-
ion of the FHS.1_ The FHS has defined frank
besity as an FRWI of 120.0% or greater? A
omplete description of the FRWI, its derivation
nd formulae have been reported elsewhere."
“he FHS and many other major epidemiological
tudies have reported a substantial correlation
vetween obesity and CHD.**

The National Health Survey (NHS) at its
960-1962 inception measured the heights and
reights of a population sample statistically
ufficient to be representative of the whole Amer-
3an population.’®?° The linear regression equa-
ion, calculated from the smoothed means of the
veight/height distribution of their male popu-
ution segment, was virtually identical to that

which describes the males of the FHS at its
1950 inception.2* In general, the NHS findings
concerning the relation of anthropomorphic cor-
relates of obesity to several types of heart dis-
ease??? parallel those of the FHS.**

Because of the quantitative relationship estab-
lished by the FHS between the FRWI and CHD,
and because the FRWI may be applicable coin-
cidentally to the whole American male popula-
tion, this same index was used in two of our
statistical studies on screening factors for poten-
tial CHD susceptibility in major segments of the
male airman population.**#* All data used in
both these studies*! ** were obtained from current
aeromedical certification files. All data were used
on a “best available” basis.

During the first of these two statistical studies*
several varieties of height errors were revealed
serendipitously. An analysis of these errors
evolved as an adjunct to the main purpose of
attempting their correction wherever possible.
Because of the relevance of these errors to stated
height and because all stated-type data are vul-
nerable to substantial error,’** a convenience
sample of stated weights of ATCs from an FAA
facility was analyzed for possible errors. The
results of the height and weight error analyses
are reported here.

II. Methods

Height Error Analysis. In one of our pre-
vious statistical studies** the population sample
consisted of 23,826 ATC personnel. Of these,
we noticed that 104 possessed stated heights of
59 inches or less. We became particularly sus-
picious during this study that these were errors
in height because the minimum height standard
for recruitment of new ATC personnel has been
65 inches since 1965.27 We conducted a retro-
spective examination of the height data on the
674 personnel listed at 65 inches or less. First
we examined all available previous aeromedical



It is hoped that this revelation of stated height
and stated weight errors generated at the pri-
mary source of the data may aid examining
physicians in their continued zealous efforts to
provide medical data of the highest quality. As
a logical sequitur of improved height and weight

20 .

is)
T

OVER-
STATED
WEIGHT)

(Ibs)

UNDER-
STATED
WEIGHT

(Ibs.)

20F

LINEAR REGRESSION:
X= 28.3704-0.3056 Y

30

data, CHD susceptibility screening for earlie
detection of this disease entity should be en
hanced by their use in the FRWI. Any improve
ment in CHD screening should also result in thi
enhancement of aviation safety.

Y .

! 1 L n A 1 A

80

100
ACTUAL FRWI (%)

{
I40

Ficure 2, A graphical plot of understatement or overstatement of weight (in pounds) versus the actual FRWI (i
percent) calculated from the measured values of height (in inches) and weight (in pounds).


A CAMI Flight Surgeon was detailed to the
articular ATC facility for four discontinuous
ne-month periods during one calendar year.
lis primary duty in each period was to examine
iose personnel whose required annual aeromedi-
ul certification examinations were due. A total
f 206 such examinations were accomplished in
ie four months.

Before each examination the examinee filled
ut the standard airman medical application in
ye usual manner, including the entry of stated
eight and stated weight. The Flight Surgeon
reasured both height and weight in inches and
ounds during the examination, using standard
redical height and weight scales. In accordance
‘ith the FHS procedure, both measurements
‘ere obtained on each examinee with shirt and
ioes previously removed. The stated weights
ere compared with the measured weights.

UL. Results
Height Error. Of the 674 stated heights of
5 inches or less, a total of 216 were in error.

AGE

Incorrectly stated height accounted for 82.8%
of these errors. Table 1 presents the frequency
distribution of stated height, correctly stated
height, incorrectly stated height and percent in-
correctly stated height versus height category.
One can readily see that the 104 heights stated
as 59 inches or less were all in error. The error
fell appreciably to 44.8% at the stated height of
62 inches and appeared to be approaching zero
asymptotically at the stated height of 65 inches.

These height corrections were made as a small
portion of a much larger study** which involved
the analysis of data from the entire ATC popu-
lation of 23,826 personnel. In this study* the
distributions of simple parameters such as systolic
blood pressure (SBP), diastolic blood pressure
(DBP) and heart rate (HR) in an age versus
FRWI table format were examined for patterns
related to increasing susceptibility to CHD. As
illustrated diagrammatically in Figure 1, an in-
crease in a CHD susceptibility parameter in the
vector shown by the arrow is indicative of an
increasing susceptibility to CHD. Although

(yrs)

FRWI

(%) =30 30-39

40-49

>50 All Ages

=|00.0

100.0-
119.9

2120.0

All
FRWIs

tcuRE 1. Diagrammatic representation of the age versus

FRWI table format.

parametric direction of an increasing magnitude of susceptibility to CHD.

3

The vector arrow indicates the



certification records of individuals with question-
able height data; then, where possible, we certi-
fied or corrected the information on the particular
individual. Two general types of height error
were revealed: stated-height error and data-
transfer error.

The stated-height error is ascribable to the
airman and occurs during the filling out of the
medical application which requests the height in
inches. Many airmen enter their correct height
in numbers but omit the appropriate symbols for
feet and inches. For instance, an airman may
enter the number 56 and mean 5 feet-6 inches but
if the symbols for feet and inches are not in-
cluded, the information is transferred into the
aeromedical certification data files as 56 inches
and a substantial error of 10 inches is introduced
into the data system. This magnitude of height
error introduced into the calculation of the
FRWI results in a gross overestimation of the
degree of obesity of the individual.

The second type of height error was ascribable
to the key-punch operator during the transfer
of data from the airman’s application into the
aeromedical certification data files. This type
of error is of historical interest only, because
shortly after 1967 revision of data-transfer pro-
cedures and adjunct data-editing checks resulted
in its virtual elimination.

Weight Error Analysis. Previous anthropo.
metric studies’ *’ showed that stated weight ic
also vulnerable to a substantial degree of error
heavy men tend to underestimate and light one:
tend to overestimate their weight. Since statec
weight is one of the parameters used in ow
calculation of the FRWI, any substantial erro:
in stated weight should affect adversely the ac
curacy of the calculated FRWI. Because of thi
possibility of this type of error in our use o:
stated weight, a small aliquot test for errors wa:
conducted at an ATC facility.

Tapre I, Frequency distribution of stated height, correctly stated height, incorrectly stated height and percen
incorrectly stated height versus height category.

FREQUENCY %
HEIGHT STATED CORRECTLY INCORRECTLY INCORRECTLY
CATEGORY HEIGHT STATED STATED STATED
(inches) (ALL) HEIGHT HEIGHT HEIGHT
=59 104 0 104 100.0
1
60 44 4 40 90.9
61 20 ! 19 95.0
62 29 16 13 448
63 46 34 12 26.1
64 147 135 12 8.2 ;
65 284 268 16 5.6



Taste III.

The quantitative redistribution of mean SBP (in mm Hg) effected by the correction of 216 stated-
height errors in the whole ATC population of 23,826 personnel.

In each table cell, the upper number is the un-

corrected value and the lower number the corrected value of mean SBP.

AGE (yrs)

FRWI

(%) __— <30.~——«30-39 == «40-49, = >50_ All Ages
120.7 121.2 123.8 127.9 121.8
=i00.0
120.7 120.1 123.7 127.8 121.8
looo-|| 1250 | 1253 | t2a1 | 1312 126.3
119.9 125.1 125.4 128.2 131.0 126.3
129.6 130.2 132.6 133.6 130.7
2120.0
130.9 131.3 133.1 136.2 131.9
All 1225 123.4 126.2 129.6 124.0
FRWIs 1225 123.4 126.2 1296 124.0
overweight. Figure 2 presents a graphical plot IV. Discussion

of the understatement or overstatement of weight
‘in pounds) versus the actual FRWI (in per-
vent) calculated from the measured values of
reight and weight. The linear regression equa-
jon for the distribution of plotted points in
Figure 2 is K=28.3704—0.3056Y. According to
his distribution of the 206 data examined, the
werage understatement of weight at an actual
FRWI of 120.0% was 8.8 pounds and the aver-
ige overstatement of weight at an actual FRWI
rf 80.0% was 3.8 pounds. Statistical analysis
revealed that this regression distribution differed
‘ignificantly (p=<0.01) from one manifesting
sero understatement or overstatement of weight.
Due to such understatement of weight by grossly
wverweight individuals, when the height data
san be assumed to be correct, the FRWI classi-
ication of obesity (120.0%) based on stated
veight may be viewed as a conservative judg-
nent.

Our two previous statistical studies on screen-
ing factors for potential CHD susceptibility re-
vealed the usefulness of the FRWI as a
quantitative indicator of obesity.2*?* As used
by the FHS, the FRWI is based on measured
values of height and weight;? as used in our two
CHD screening factor studies,?**° the FRWI
was calculated from stated-type data. As di-
rectly relevant to both screening studies, the cor-
rection of the height and weight data in the
directions and general magnitudes indicated in
the respective error analyses would serve to
strengthen considerably the screening power of
the conclusions reached in both those studies.” **
On the standard airman medical application, the
replacement of stated height and stated weight
by measured values would aid substantially in
strengthening the screening power of age/FRWI
distributions of CHD susceptibility parameters.



TECHNICAL REPORT STANDARD TITLE PAGE

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.
FAA-AM- 73-10

4, Title and Subtitle 5. Report Date

HEIGHT AND WEIGHT ERRORS IN AEROMEDICAL June_1973
CERTIFICATION DATA 6. Performing Orgonization Code

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

Michael T. Lategola, Clyde A. Lynn, Earl D. Folk,
Charles F. Booze, Jr., and Peggy J. Lyne

9. Performing Orgenization Name and Address 10. Work Unit No.
FAA Civil Aeromedical Institute
P. 0. Box 25082 TI. Contract or Grant No.

Oklahoma City, Oklahoma 73125

13. Type of Report and Period Covered

12. Sponsoring Agency Name and Addre:
Office of Aviation Medicine

Federal Aviation Administration
800 Independence Avenue, S.W. 14. Sponsoring Agency Code
Washington, D.C. 20591

15. Supplementary Notes

Work was performed under Task No. AM-B-71-PHY-2

16. Abstract
‘he Framingham Relative Weight Index (FRWI) of obesity was described in previous

‘eports as a screening aid for detecting susceptibility to coronary heart disease
CHD). FRWLI calculation requires measured values of height and weight but the
eight and weight values on standard airman medical applications are usually stated
stimates of the examinee. Because such stated (unmeasured) data are vulnerable to
rror, samples from aeromedical certification sources were examined for errors.

n a previous study 674 Air Traffic Controllers (ATC) stated their heights at 65
nches or less, These low values were scrutinized as suspect because the minimum
eight standard for ATC recruits has been 65 inches since 1965. Of 216 corroborated
rrors 179 were due to incorrectly stated height. The stated-height error exerted
concentrated effect through false overestimation of the FRWI.

n a separate study, the stated and measured weights of 206 ATC personnel were
ompared. The degree of stated-weight error was substantial and was directly
roportional to the degree of underweight or overweight. Due to weight understatement
y grossly overweight individuals, the 120.0% FRWI classification of obesity based
n stated weight is quite conservative.

17 Key Words 18, Distributien Statement
tated Height; Stated Weight; Coronary Availability is unlimited. Document may be
eart Disease; Aeromedical Screening; released to the National Technical Informa-
besity; Blood Pressure; ATC Personnel; tion Service, Springfield, Virginia 22151,
ge for sale to the public.

19. Security Classif, (of this report) WH. Security Clessil. (of this page) TH. No. of Pages | 22. Price
Unclassified Unclassified 7 $3.00

orm DOT F 1700.7 (8-69)





pa

2

. Kannel, W. B., T. R. Dawber and P. 3

. Marks, H,. H.: Influence of Obesity on Mor

. Stamler, J.,

. Pell, S. and (. A.

. Paul, 0.

}. Spain, D. M., D. J. Nathan and &

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P. M. McNamara: Relation of Body Weight to De-
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1967.

McNamara:
Detection of the Coronary-Prone Adult: The Fram-
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Revotskie: Epidemiology of Coronary Heart Disease,
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W. B. Kannel: Predicting Coronary Heart Disease
from Body Measurements of Framingham Males.
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» Kannel, W. B., R. Brand, J. J. Skinner, Jr, T. R.

Dawber and P. M. McNamara: The relation of
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and Mortality. BULL. N. Y. ACAD MED., 36:296,

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H. A. Lindberg, D, M. Berkson, A.
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D'Alonzo: Three-Year Study of
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21, Lategola, M. T.: The Use of Simple Indicators for
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Taste II, Frequency distribution and percent prevalence of stated-height errors in the whole ATC population o
23,826 personnel. In each age/FRWI table cell, the top number is the stated-height error frequency, the middl
number is the total number of height data and the bottom number is the percent prevalence of stated-heigh

FRWI AGE (yrs)
(%) =<30 30-39 40-49 >50 All Ages
14 10 4 4 32
=100.0 5487 4935 2086 809 13,317
0.3 02 02 0.5 0.2
32 21 5 \ 59
100.0-
119.9 286! 4009 1927 760 9,557
i 05 03 0.1 06
~ 46 50 19 10 125
2120.0 294 400 194 64 952
15.7 12.5 98 15.6 13.1
92 8! 28 15 216
ras 8642 9344 4207 1633 23,826
im 0.9 0.7 0.9 0.9

none of the average values, per se, of SBP, DBP
and HR in each age/FRWI table cell was con-
sidered to be medically abnormal, the general
pattern of increase in these three parameters
with age and FRWI (arrow vector in Figure 1)
was considered to be indicative of an increasing
CHD susceptibility because the percent preva-
lence of the medically documented 400 cardio-
pathology series in the same 23,826 ATC
personnel followed the same general pattern.
The effect of 216 height errors on the quantita-
tive distribution of 23,826 height data would
ordinarily be considered quite negligible. This
would be correct if the errors were distributed
diffusely throughout the whole spectrum of
height data. However, this was not the case
since a concentration of 75.5% of the 216 height
errors occurred in the stated-height category of
61 inches or less. A further reflection of this
error concentration is shown in Table II wherein
the percent prevalence of height error in the

FRWI category was 120.0% or greater exceed
by several orders of magnitude those of the tw
lesser FRWI categories.

An example of the quantitative redistributio.
of a CHD susceptibility parameter (SBP
caused by the correction of the 216 stated-heigh
errors is shown in Table III. The mean SB)
values showed the largest corrected increases i
the table cells whose FRWI was 120.0% o
greater. In general, the corrections intensifie
the degree of SBP increase with age and FRW
as diagrammatically represented in Figure °
Although the total percent prevalence of statec
height error was only 0.9%, the concentration ¢
this type of error has a substantial effect on th
degree of intensity of a CHD susceptibilit
screening parameter such as SBP.

Weight Error, In general agreement wit
previous human anthropometric studies,’ 2" th
degree of error in stated weight was direct]
proportional to the degree of underweight c




ACKNOWLEDGMENTS

The authors sincerely acknowledge the substantial contribution of Dr.
Audie W. Davis, Jr. and his staff during the phases of this study which re-
quired facilitated access to current and historical Aeromedical Certification

data files. Also, we sincerely acknowledge the efforts of Mrs. Paula Grape
in several manual facets of data processing.