First post, new SPSS user, struggling with Complex Samples functions.
SPSS ver. 16 on windows 7.
I'm working on a survey, stratified (in provinces), 40 cluster (County) selected with systematic PPS in every Province, then one Village selected (simple random selection) in every cluster/County and 20 cases selected (simple random selection) in every Village. Cluster could be selected twice Some clusters have been selected twice, due to their large size, so I suppose that I should consider this a WOR method for PPS.
However when I want to calculate the weighing factors with SPSS complex samples, and I chose the PPS systematic option I think SPSS consider it as WOR sampling. In fact at the end of the procedure I got this message: ""the maximum Measure of Size (MOS) value across population units cannot be greater than the total MOS in the population divided by the samples size." which I think means that one or more clusters are so large that they would be reselected, which is not compatible with the systematic PPS WOR method, and so the error message.
If on the other side a select a 'simple' PPS and then chose a WR method, SPSS would not allow a second stage of sampling.
So my questions are:
(i) is systematic PPS always WOR?
(ii) why SPSS does not allow multiple stage sampling when WR sampling is selected at first?
(iii) what would be the best procedure to estimate weighing factors in this survey?