The changes of retail use in Plymouth’s centres from 2012 to 2015; increased vacancy rates in the city centre

Order Instructions/Description
I need assistance with writing the methodology section of an assignment.

I have carried out a retail survey of the 51 local centres around Plymouth City Council. I have looked at the use classes for about 2,000 units so that I can see the amount of vacancy rates and A1 uses. This is so it can be compared to the data gathered on the other years.

I need it to include information about a retail survey as a methodology, and the limitations of the method.