RDC News: Longitudinal Administrative Databank (LAD) available

The LAD is a sample of individual taxfilers with a longitudinal design. Currently data are available from 1982-2014. The frame is constructed from the annual T1 Family File (Annual Estimates for Census Families and Individuals (T1 Family File)) which makes use of information from administrative files. Only individual records that have social insurance numbers can be selected for the LAD and these are sampled at a 20% rate. Also included in the LAD are a set of immigration variables, drawn from the Longitudinal Immigration Data Base (IMDB), relating to information collected at landing, as well as a set of variables describing Tax Free Saving Account usage.

The LAD survey units are individuals but limited information about the characteristics of their family during the reference year is also kept (e.g. spouse/parent, family, and children). No stratification is performed as the sampling weight is equal across all units. The sampling is done once on each record in such a way that if someone is selected in a particular reference year, they will be selected in any other later (or earlier) years in which they are present in the T1 Family File.

Researchers unfamiliar with administrative tax data are cautioned that not all LAD data are internally or externally coherent, in part, because tax data are not subject to the same edit and imputation procedures as survey data. Consequently, many researchers have found it takes some time to become familiar with the LAD and to be able to operationalize it in their research.

Note: Potential researchers would benefit from reading the LAD Data dictionary (or the “technical reference guide” as it will soon be known) as part of their understanding of the database.