Hypothetical errors and plateaus: A response to Newman

Abstract

Newman questions recent claims about a plateau in mortality rates for Italians beyond age 105 on the basis of a hypothetical model. His model implies implausibly high error rates for extreme ages. For individuals over 110, for whom birth certificates have been collected, the form in which Italian births were registered precludes the kinds of clerical errors in year of birth that Newman assumes.

Late-life mortality is underestimated because of data errors

“…Newman demonstrates that rare cases of age misreporting among people in their eighties eventually result in accumulation of false claims at extreme old ages and produce spurious mortality deceleration [25,26]. Regardless of possible limitations of his simulation model (as Wachter [27] rightfully pointed to significant age exaggeration in Newman’s model), this study is important because it brings our attention to the fact that even rare cases of age misreporting are able to produce spurious mortality deceleration. Currently, information about quality of age reporting at extreme old ages is hardly ideal even in countries with good vital statistics.…”

“…Currently, information about quality of age reporting at extreme old ages is hardly ideal even in countries with good vital statistics. Italian data used by Barbi and colleagues [28] have apparently a good quality for ages 110 years and over, because these records were validated using birth certificates [27]. However, for ages 105 to 109 years, the quality of data remains uncertain because the authors do not outline in detail what they did to verify and clean the data and what is the percentage of incorrect age reporting.…”

“…However, for ages 105 to 109 years, the quality of data remains uncertain because the authors do not outline in detail what they did to verify and clean the data and what is the percentage of incorrect age reporting. Wachter suggests that age misreporting in data used by Barbi and colleagues should be minimal because Italy has a well-established registration system [27]. But are Italian data really free of errors?…”

Supercentenarian and remarkable age records exhibit patterns indicative of clerical errors and pension fraud

“…The US data support the hypothesis that improved vital registration should reduce the number of supercentenarians, and be associated with changing patterns of old-age survival, by reducing age-coding error rates [16]. Likewise, findings from the Italian data support the hypothesis that these ‘semisupercentenarians’ largely constitute a collection of age reporting errors [18].…”

“…Post-validation errors in these Italian data were assumed to be minimal on the basis of a belief [27]. Subsequently, it was acknowledged that an unknown number of errors in these data could not be detected using documentary evidence, as “ Occasionally…a mistake will escape even a rigorous validation procedure ” [18]. Finally, it was proposed that the occurrence of such errors, which cannot be detected using documents, must be rare or “ essentially impossible ”, because of the high quality of documents used to compile these data [18].…”