Westat has contributed to the sample design and survey data collection for NHANES, and has a statistical software package (WESVAR) that you can download and use to analyze survey data. We do not offer much in the way of support for users, other than standard documentation, but on the other hand we do not charge users licensing fees for using the programs. See the Westat web site (www.westat.com) for official information about WESVAR and instructions for downloading the programs. As a rule, corresponding SAS estimation methods produce the same parameter estimates as WESVAR, but WESVAR calculates adjusted (wider) estimates of the variance of estimates from data collected under complex survey designs. Sig

____________________________ Question ________________________________ Hi All,

I am just starting a project using the NHANES-I (National Health and Nutrition Examination Survey) data. NHANES is a three-stage, stratified probability sample. The data contains a series of weights, PSUs (primary sampling units) and strata. I am at a complete loss as to how to use these weights, etc.. The project I am working on involves computing the prevalence of a rare disease so the weighting will be especially important. Some of the NHANES documentation refers to a number of software packages specially designed to deal with these issues. I am pretty much restricted to working either in SAS or S-Plus. ANY help or advice the group can give me would be greatly appreciated. Especially SAS code or references.

I will summarize and post to the group any replies received.

Thanks in advance. John

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John Oehlert Statistical Programmer/Systems Analyst Division of Biostatistics HRP Redwood Building, Rm T100 Stanford, California 94305-5405

Voice: (650) 725-2925 Fax: (650) 725-6951 Email: joehlert@leland.stanford.edu

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