state by state abuse rates

Since I am not a specialist in these areas, perhaps you can help me understand what may be going on here.

I have been comparing rate of substantiated abuse/neglect rates using CWLA's state fact sheets--2007 (these are based on 2004 data). Rates are all over the place--from a low of under 2 per thousand (Pennsylvania) to the high 20's. More to the point, rates are wildly inconsistent within geographical regions of the country, or between states that would not appear to be demographically all that different. I have noticed in the past that there are inconsistencies within reported rates of some forms of abuse/neglect, particularly psychological maltreatment--one state may report that half of children substantiated have experienced psychological maltreatment while an adjoining state reports a rate of 1 to 5 percent.

The question I have is how does one make sure apples are being compared to apples and what drives these differences? One might certainly compare rates at which various risk factors occur, one might certainly compare economic and demographic data, but to what extent is it simply a matter of definitions, applications, and whether these are consistently applied? To what extent it is a matter of public policy from one state (or other type of defined region) to another?

Sheri McMahon