I have a researcher who is seeking a correspondence file linking 2011 or 2006 CSD codes to 1976 CSD codes. My suspicion is that any correspondence files that exist are specific to successive Censuses (i.e. one Census to the previous Census) and do not span the broader time period being asked about. I’d be pleased to hear otherwise.
The short answer is correct, in general we do not have correspondence files for time spans longer than one census to the next. Also, we normally do not do a correspondence file at the CSD level. We do it for the lowest levels of geography, EAs, DAs, or DissBs. So, there is no such product that we can just send out to the client. That being said, here are a couple of other points to consider:
1. The concept of the Standard Geographical Classification (SGC) came into existence around 1971/1976. The CSD information I see available then does not follow the standard Pr(2)/CD(2)/CSD(3) code structure that we use today. I believe the CSDs that existed then are conceptually the same… municipalities, indigenous reserves, etc. However, I would need to confirm that with subject matter, to make sure the client was getting the relationship that was requested.
2. We do have the GAF from 1976 which does contain rep pts for each EA, and the code for the CSD that an EA belongs to. In theory, we could use those rep pts, and overlay them with the 2006/2011 CSD boundaries, and do an analysis to create a relationship between the 1976 CSDs and 2006/2011 CSDs.
Normally custom work for clients external to StatCan goes through the Regional Offices since it would be cost recovery. No such file, but one could be created (not sure by whom) if the client requests it.