I have been asked to provide some advice on a study examining differences in mortality rates between a cohort of individuals followed from the 1960s to now, with deaths recorded in every year. I want to get a sense of whether the overall mortality rate in my cohort differs from that of the general population. I have considered using death numbers from my national census as a comparison sample.
The previous analyst on this project has suggested using data from a single census (2010) as a comparison point and to compare the number of deaths in 2010 to the overall number of deaths in my cohort. This seems to me to be confounded by the fact that the cohort contains deaths from several different years and the census data contains deaths from only one year. I have tried to find articles or books that discuss the approach one should take when comparing mortality between a study cohort and the general population. But, I can find nothing. Can someone please point to any resources or provide advice. If I am not explaining myself well, I am happy to clarify.
Thanks in advance.