Delay-Adjusted Rates in SEER*Stat
In the April 2019 release of the 1975-2016 SEER Research Data, delay-adjusted rates (age-specific and age-adjusted) can be computed in SEER*Stat using delay-adjustment factors derived from the December 2018 NAACCR submission. Delay adjustment factors and rates can be produced for the SEER 9, SEER 13, and SEER 18 groups of registries. The delay-adjusted and unadjusted rates presented in the SEER Cancer Statistics Review can be obtained from this database. Delay-adjusted rates are computed using weighted averages of the cases.
Since delay factors are specific to a cancer site, registry, age group, race, ethnicity, and year of diagnosis, there are no explicit delay factors for estimates that are aggregates of these groups. However, SEER*Stat computes "composite" delay factors, computed by dividing a delay-adjusted rate by the unadjusted rate. These "composite" delay factor represents a weighted average of the underlying factors, weighted by the number of cases in each stratum. The variances of the delay-adjusted, age-adjusted rates are obtained by assuming that the delay factors are constant and cases follow Poisson distribution.