Can this dissertation topic be solved? Is the topic too broad and would be hard to study? You do not want to begin your research and discover that it would take a ten years or even more to investigate the dissertation topic. During this time, another person could pick out this same topic or resolve the issue using completely different procedures. Also, do the research to discover if this problem can even be settled. How terrible would it be if you spent many months or even years on investigation to find out that the matter was never solvable to begin with?