I'll respectfully disagree.
The fact that the data is from 1915 - 1920 does not invalidate it unless you want to suggest that human nature in 1915-1920 is different than it is now - which would seem a strange point to defend. And the sample sizes are quite decent.
I know that the HM userbase had a tendency to dismiss studies that are incorrectly conducted, but I don't think that this is one of those cases.