35 million cases, 95 questions and 7 complete-count census datasets: Coding variables for The Canadian Peoples project

The Canadian Peoples project (TCP) has collaborated with Ancestry to prepare for research a series of Canadian historical census microdata files encompassing the years 1851 to 1921. This article describes the work of team at the Programme de recherche en démographie historique (PRDH, Université de Montréal) to code and transform these very large data files. The main challenges encountered in this project centered on the need to code data which was not transcribed in-house but rather by Ancestry. The extent and quality of census transcription varied from year to year and from question to question, with coverage improving for the twentieth-century enumerations.