The register extract I use here covers the period between 1990 and 2005. The information from the Register of Deaths and the Migration Register are given on a daily basis, meaning that the exact day of the event is known. The information from the Family Register, the Education Register and the Income Register is only updated annually, which means that the data are based on the individual’s status at January 1 of each year during the observation period.
The variables personal identification number of the partner, wealth, municipality of residence, and citizenship were coded as time-varying covariates. Continue reading “The research plan was to test whether the age difference between the spouses affected both sexes in the same way”