I discovered a (probably) major flaw in my research design.
I am examining investors and their investment performance. Or in other words, I want to investigate if some investors are better than others.
I collected data on particular investments of 10 different investors.
Finally I got a small dataset containing 50 investments. Now I am very concerend because of the assumption of independence of observations.
Clearly, those 50 investments aren't independent because many of them were financed by the same investor. However, isn't this exactly what I want to find out?
If I can't change my research design anymore, is there any way to deal with this issue?