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Validation of the Anthropometry Dataset.
The PeopleSize method was validated with the 2008 dataset, against two
'gold standard' population surveys: the
National Health and
Nutrition Examination Survey (NHANES) conducted by the US
Government, and the
Health Survey for England conducted by the UK Government.
Both these surveys are part of regular long-term monitoring
activities, which have the best sampling procedures and the best
statistical treatment of the data, to ensure that they are
representative of the population. They are particularly
effective at persuading pre-selected individuals to agree to participate,
and so the samples are more accurate than clothing and other
one-off surveys.
Clothing surveys characteristically show
populations to be
taller and lighter than they really are, because the shortest and
heaviest individuals more often decline to participate.
The NHANES data were collected in 2003-6, and the HSE data in
2005. For this test, old survey data from 1991, 1993 and 1956 were
fed into the PeopleSize process, then their updated values were
compared with the benchmark new data.
Men 18-64 |
2003-6
Survey 5%ile |
PZ2008
5%ile |
2003-6
Survey 95%ile |
PZ2008
95%ile |
Error
5%ile |
Error
95%ile |
PZ
source year |
Waist Circumference, at the midpoint |
780 |
794 |
1189 |
1172 |
1.8% |
-1.4% |
1993 |
Hip Circumference, maximum |
935 |
931 |
1190 |
1190 |
-0.4% |
0.0% |
1993 |
Upper Leg length, surface |
371 |
373 |
480 |
486 |
0.5% |
1.3% |
1991 |
Calf circumference, maximum |
340 |
331 |
466 |
469 |
-2.6% |
0.6% |
1956 |
Upper Arm circumference, at the midpoint |
278 |
281 |
417 |
416 |
1.1% |
-0.2% |
1991 |
Waist Circumference, abdominal |
770 |
768 |
1271 |
1240 |
-0.3% |
-2.4% |
1991 |
Thigh circumference, at the midpoint |
454 |
454 |
652 |
637 |
0.0% |
-2.3% |
1991 |
Women 18-64 |
|
|
|
|
|
|
|
Waist Circumference, at the midpoint |
682 |
665 |
1104 |
1081 |
-2.5% |
-2.1% |
1993 |
Hip Circumference, maximum |
904 |
895 |
1276 |
1259 |
-1.0% |
-1.3% |
1993 |
Upper Leg length, surface |
332 |
339 |
434 |
443 |
2.1% |
2.1% |
1991 |
Calf circumference, maximum |
321 |
324 |
473 |
471 |
0.9% |
-0.4% |
1956 |
Upper Arm circumference, at the midpoint |
243 |
241 |
422 |
428 |
-0.8% |
1.4% |
1991 |
Waist Circumference, abdominal |
715 |
692 |
1240 |
1248 |
-3.2% |
0.6% |
1991 |
Thigh circumference, at the midpoint |
431 |
432 |
685 |
673 |
0.2% |
-1.8% |
1991 |
|
|
|
average error |
0.0% |
-0.1% |
|
|
|
These results allow us to have good confidence in the PeopleSize
data, particularly in view of the fact that these are the most difficult
fatty dimensions, and at 5th and 95th percentile not just the average.
Overall the updating process was close to perfect, with individual
dimensions within about 3% margin.
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