Is size a confounding variable here? My guess is smaller tech companies with less competitive salaries and narrower recruiting pipelines (and therefor more diff

Is size a confounding variable here? My guess is smaller tech companies with less competitive salaries and narrower recruiting pipelines (and therefor more difficulty hiring underrepresented groups) would be more likely to make this pledge, whereas larger companies would have more trouble getting the pledge through legal and PR departments. edit: I notice this study was conducted on 240 of the "most prominent" tech companies, not sure if that implies that they are of similar size though.