Methodology of studies evaluating death certificate accuracy were flawed.
OBJECTIVE
Statistics on causes of death are important for epidemiologic research. Studies that evaluate the source data often give conflicting results, which raise questions about comparability and validity of methods.


METHODS
For 44 recent evaluation studies we examined the methods employed and assessed the reproducibility.


RESULTS
Thirty studies stated who reviewed the source data. Six studies reported reliability tests. Twelve studies included all causes of death, but none specified criteria for identifying the underlying cause when several, etiologically independent conditions were present. We assessed these as not reproducible. Of 32 studies that focussed on a specific condition, 21 provided diagnostic criteria such that the verification of the focal diagnosis is reproducible. Of 16 that discussed the difference between dying "with" and "from" a condition, eight described how competing causes had been handled. For these eight, the selection of a principal cause is reproducible, but in three the selection strategy conflicts with the international instructions issued by the World Health Organization.


CONCLUSIONS
Methods and criteria are often insufficiently described. When described, they sometimes disagree with the international standard. Explicit descriptions of methods and criteria would contribute to methodologic improvement and would allow readers to assess the generalizability of the conclusions.
Johansson
Lars Age
LA
Centre for Epidemiology, Swedish National Board of Health and Welfare, SE-106 30 Stockholm, Sweden. lars.age.johansson@socialstyrelsen.se
Westerling
Ragnar
R
Rosenberg
Harry M
HM
D002423:Cause of Death; D003644:Death Certificates; D016021:Epidemiologic Studies; D006801:Humans; D008499:Medical Records; D011786:Quality Control