Specificity of Statement of Purpose--Comparative Politics

[sinni]

Hello,

I am new to the site, so apologies for any redundant questions.  I am a few years out of school with a BA in Poli Sci/Econ and an MA in Area Studies.  I am looking to go back for a Comparative Politics PhD. I work in international development, not in academia or policy, so have no new research I can write about it my statement. I don't have anyone who can seriously work through my statement with me, and I feel like I am already asking a huge favor of professors writing my recommendations who have not seen me for almost a decade. I know my general areas of interest, and know who I want to work with at perspective schools, but I my question is how specific should my research question be in the SoP? Do I need to talk at length about others doing similar research?   Do I need to know which countries/populations I want to hone in on?  If intensive methods courses are part of the PhD, how can I identify which I will be using before taking any of them?  

For example--I have taken econometrics, but presumably this knowledge will deepen during the program, as will my use of qualitative methods.

I have learned from my 2 year MA experience that interests change, and projects evolve and shift over the course of study. Sometimes you realize that your question is too ambitious or unanswerable, and you need to narrow your question. It seems very presumptuous to lay out a very detailed question without the preliminary work. 

If anyone has any tips here, please share.