```Date: Tue, 9 Sep 2003 15:26:28 +1000 Reply-To: Frank Milthorpe Sender: "SPSSX(r) Discussion" From: Frank Milthorpe Subject: Re: Weighting Data Content-Type: text/plain; charset=US-ASCII Kathleen If you have a large number of population segments you can automate the process using SPSS syntax. Essentially you need an external file with the population control totals for each segment. Using the AGGREGATE COMMAND you determine the number of survey observations in each segment. The aggregated file is then merged with the population control totals. On this file you can calculate the weight for each segment. This is then matched back onto your original data file. This is very useful if you have 100 segments; less useful if you have only a few categories. This avoids the need to re-enter data. The approach I have outlined above is the one that would adopt for weighting survey observations where there are 100 survey observations for population of say 2000000. You appear to be undertaking a different weighting process to adjust the proportions. The same approach can still be applied. I hope this helps. Regards Frank Milthorpe -------------------------------------------- Frank Milthorpe Transport Modelling Manager Transport Data Centre Department of Infrastructure, Planning and Natural Resources GPO Box 1620, Sydney NSW 2001 Level 17, 227 Elizabeth St, Sydney Tel: +61 2 9268 2937 Fax: +61 2 9268 2853 Email: frank.milthorpe@transport.nsw.gov.au >>> Kathleen Tobin-Flusser 09/09/03 00:20 >>> I currently use this syntax to weight data to certain population parameters: COMPUTE secwt = 21.6/13.4*(sect=1) + 11.8/14.5*(sect=2) + 24.9/26.3*(sect=3) + 16.8/21.8*(sect=4) + 9.7/10.7*(sect=5) + 15.2/13.2*(sect=6). COMPUTE genwt = 49/40.7*(sex=1) + 51/59.3*(sex=2). COMPUTE wtfactor = secwt*genwt. weight by wtfactor. I would like to know what other options there are for weighting 1) within SPSS and 2) solutions that export data to other software to assign weights using more complex wieghting (ie RIM) and then pulling the data back into SPSS for analysis with those weights. Thanks, KT Kathleen Tobin Flusser Senior Research Associate Marist College Institute for Public Opinion www.maristpoll.marist.edu 845.575.5050 ```

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