Sample weights are added to the files by using the spreadsheet weights.xls and the SPSS programs weights_table.sps, weights.sps and weights_merge.sps. All these files can be found in the data processing sub-folder. The spreadsheet is used to calculate the sample weights. It has two worksheets, calculations and output. The calculations worksheet performs the calculations. The output worksheet contains only the sample weights and a list of cluster numbers; this format is useful for reading the data into SPSS. The program weights_table.sps produces data needed for calculating the sample weights. The program weights_merge.sps adds the appropriate sample weights to the analysis files. The program weights.sps, which you will never directly execute, describes the structure of the data in the output worksheet.