Validation of Exceptional Longevity

Age Validation of Han Chinese Centenarians



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The Whipple's Index for evaluating the general degree of age heaping in a population of all ages is usually calculated as:

The Whipple's Index =

(sum of numbers at ages 25, 30, 35, ..., 60) x 100 x 5
total number between ages 23 and 62

The value of the Whipple's Index in a population with perfect age reporting as well as no large changes in fertility, mortality and migration for a long time would be 100. The United Nations recommended a standard for measuring the age heaping as follows:

Whipple's Index Quality of Data Deviation from Perfect
<105 very accurate < 5%
105-110 relatively accurate 5-9.99%
110-125 OK 10-24.99%
125-175 bad 25-74.99%
>175 very bad >= 75%

The choice of 23 and 62 as the limits of age band to be examined in the classic Whipple's Index calculation is arbitrary but has been found to be the most suitable for the purpose of measuring age heaping in general in a population of all ages (United Nations 1955, pp. 39-45). However, this age band cannot be used for the centenarians since it excludes persons above age 62. We, therefore, define that the Whipple's Index for the centenarian survivors or deaths of age x and over as follows:

The Whipple's Index for centenarians =

(sum of numbers at ages 95, 100, 105) x 100 x 5
total number between ages 93 and 107

The lower age limit (x) is 95. The reason why 100 is not chosen as the lower limit here is that a too small sample size and a too quick decrease of the numbers after age 100 may not produce meaningful results. As shown in Table 4, the values of the Whipple's Index for the centenarian population are less than 100, due to the quick decline of the numbers of survivors and deaths at very old ages. We evaluate Han Chinese age reporting by comparing it with the Swedish counterparts, which has the best data quality in the world.

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Max-Planck-Gesellschaft 2003