He's most likely referencing his next two lines down, "As part of Google's mandatory diversity training, one is presented with Google's internal research claiming that unconscious bias is real and measurable, and that diversity hiring yields both better individual and group performance. Google has a line which they feel is backed by research..." so he can't post that data publicly as it is Google's private research.

It doesn't mean it doesn't exist though, just that we won't get access to it.