I’m helping a student who’s looking at demographic changes in a particular Saskatoon neighbourhood over time. In the 1946 census of the prairies I found a table for Saskatoon and Regina broken down by social zones, but no further explanation as to the areas of the cities to which the numbers apply. In 1951 there is a CT reference map that is similarly numbered. Did social zones morph into CTs?
Here is a map of the social zones for Saskatoon used in the 1946 Census:
On a cursory glance, they appear to be the same as the Census Tract boundaries used in the 1951 Census, but the student will need to compare them more closely.
With thanks to the U of Toronto Map and Data Library's Historical Census page for the link to the 1946 publications digitized by the Internet Archive, and the 1951 CT map.
On page 201 of Statistics Canada - Cat. No. 92-351-UPE 1996 Census Dictionary - Final Edition, under Remark:
Census tracts were called "Social Areas" in 1941 and 1946.
I would venture social zone or social area definitions were used in the 1941 and 1946 censuses. These were later replaced with census tract beginning with the 1951 census.