How does the accuracy of a stratified sample differ from that of a simple random sample?
The accuracy of a stratified sample is usually better than that of a simple random sample. It can never be worse. An increase in accuracy can be expected if: There are major differences between the stratified groups, and Within each group, there is homogeneity Using the professors as an example, there would be higher accuracy on a variable, such as an attitude question, if assistant professors had on average quite different views from associate professors, and both had different views from full professors. Also, there would have to be little difference within each group. That is, most assistant professors would think alike. This would increase the accuracy for this variable. For other variables there may not be any increase in accuracy, since there may be a large overlap in attitudes regardless of rank. When we report accuracy figures for a survey, we typically report the worst accuracy overall. On further analysis we might find that some variables have much higher accuracy. These coul
