"Also the sample size should be increased by a factor of 10."
You could say the same for just about any study. Obviously that would be a good thing. I don't know what the relevant p-values are, here, but my guess is that it's statistically significant. (I'm sure the full paper will include more statistical analysis of significance.)
I think more interesting would be to see how this varied across sector - these were all HR positions. It may be that the results would be quite different in, for example, programming positions.
In any case, it's an interesting question to be asking, and I'm glad people are doing research in it!