Please note, CRSP just completed an extensive review of their shares outstanding data for 1925-1946. The file they released in January 2015 (with data through December 2014) incorporates over 4000 changes that affect 400 Permnos. As a result, many of the returns we report for 1925-1946 change in our January 2015 update and some of the changes are large.
As I was looking at that, I actually noticed that the more recent FF numbers apparently changed a tad as well (which is a little hard to understand).
Some of the Simba historical numbers depend on the Fama-French data library (e.g. LCG: Fama and French 1972-1978), some other historical numbers depend directly on the CRSP database (e.g. MCB = US Mid Blend: CRSP Decile 3-5 1972-1978), and I suspect others (e.g. Ibbotson-originated) might indirectly depend on it.
I can help double-checking and updating the FF data, as I just imported the updated numbers in one of my own spreadsheets, but I don't have access to other sources, starting by CRSP itself.
PS. I took a quick look at the new FF averages, and they didn't change that much from previous numbers. Rest assured that small-cap value still has a solid (historical) advantage!
