I'm currently working on my thesis, more specifically I'm analyzing some data collected from researchers about the project's they're working on.
In the end, I have performed a multiple linear regression to verify which determinants (budget, team size,...) significantly influence the external impact of a research project. While the dependent variable (project impact) has been assessed from a survey (conducted among the institute's researchers), the independent variables are based on objective measures.
In such a scenario, what would be an acceptable r-square percentage? Could a low percentage be justified by the "subjectiveness" of the dependent variable? I've heard that the scientific area matters... i.e. in physics you rather need to have a r-square > 95% while in sociology > 5% might be already interesting...
Do you have any references about this?