Gaetano,

I tend to agree with your reviewer. A complete model on crime should have three dimensions--crimes, consequences, and policing. You seem to have the first two, but policing is lacking. One way to correct that might be to collect policing efforts for the area of your study, and including it in your regression. If you cannot find the data, which is always hard to come by, then try using dummy variables. As your research now stand, one might even argue that your specification is misspecified.

Good luck in your research.

Dear Lall B. Ramrattan ,

Thanks very much for your precise answer.

really I think that this kind of data are available. So, i can simply added to my final regression model.

Ok, the preceding conversation has confused me a bit, so maybe it's not necessary, but I add my answer anyway:

Undereporting bias means a bias introduced by the fact the the police recorded crime statistics do not represent the real number of crimes, as many go unreported. This can result in a measurement error and tereby cause endogeneity, as the degree of which crime is underreported might be correlated with your macro variables ( poor regions reporting less crime for instance). What your supervisor suggests now is that you control for this by including another variable, "Rule of Law", in your regression. I guess the idea is that the higher "rule of law" is, the more crimes are reported, and so it can serve as a control for underreporting bias. I find this claim somewhat dubious, as I don't see how it deals wirth the possibility of macro variables affecting underrreporting which would therby create endogeneity and biased OLS estimates. Also have no idea how such a variable would be implemented, but you seem to have found something on that.

I hope that helped,

Tim

I fully agree with Tim Umbach,

We use instrumental or proxy variable techniques in these cases.

Undereporting bias means a bias introduced by the fact the the police recorded crime statistics do not represent the real number of crimes, as many go under reported.