What are the strengths and weaknesses of secondary analysis as a scientific inquiry?

Do the following exercise as a way to learn the process of conducting secondary analysis. Choose an available data set, either from publichsed sources or other researchers, and study the measurements carefully. Based on the measurements available, try to conceptualized a research topic of interest to you. Describe, in detail, what measures will be used by you to study your topic. Describe any limitations you might encounter (e.g. missing variables or inaccurate approximates).