I am comparing two geographical areas of different levels of social capital in Britain. I found some database to do the comparison, but the areas are different in several terms. first, one area is from the north west of England and the other one is from midlands. the two areas are different in terms of size, population, type of economy, and service sector. my question is, do these indicators should be the same to do my comparative study. for example, should the areas be similar of population?