I only looked at diversity and no other factors. I did a survey which I also published here on HN and in total got back 67 usable results. Quite a small sample but enough.

I checked for a total of 7 different kinds of diversity that can be split into two broad categories:

1. Ascribed Characteristics - Things that are "visible" and others ascribe to you. Here I checked for Gender, Age, Nationality, and Race. Hypothesis here was that diversity in Ascribed Characteristics has a negative effect because it fosters non-task related conflict.

2. Achieved Characteristics - Things that people have worked for. Here I checked for type of education, level of education, industry experience, functional experience. Hypothesis here was that diversity in achieved characteristics enlarges the overall knowledge available to the company and fosters task related conflict which leads to better decisions. Therefore diversity in achieved characteristics should have a positive effect.

As mentioned before while the results trended towards what I expected the results weren't significant enough to reject the Null-Hypothesis in all cases but Nationality diversity which had a small negative effect.

To summarize what I found: The effects of diversity in founder teams of internet startups are so small that they are outweighed by many other factors that are easier to achieve than to fine tune the composition of your founder team.