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From |
Jeph Herrin <stata@spandrel.net> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: using weights with -svy- commands |

Date |
Wed, 14 Mar 2012 13:56:09 -0400 |

thanks, Jeph On 3/14/2012 12:49 PM, Stas Kolenikov wrote:

[aweight] would have been called for if you summarized the 10k functional data points into a single number, an aggregate indicator of the level of physical activity. If you are analyzing all of the available motion data, I don't see any need to specify any additional weights. Depending on what exactly you are going to undertake in your analysis, you may or may not need the [pweights] or -svy- settings (and you can always compare the results using Hausman test, see Pfeffermann 1993 http://www.citeulike.org/user/ctacmo/article/1036965). On Wed, Mar 14, 2012 at 11:48 AM, Jeph Herrin<stata@spandrel.net> wrote:All, This seems like a question that has been asked& answered before, but I can't find it in the archives. I have data which was was collected using a stratified survey design (NHANES, http://www.cdc.gov/nchs/nhanes.htm) which I have been analyzing using -svy- commands. However, for a random subset of survey respondents, additional data i collected - up to 10080 motion counts collected each minute for up to 7 days. I have summarized these motion counts various ways for each respondent, but since not all respondents have the same reporting period, there is varying degrees of precision - some respondents have only a few thousand counts, some have the full 10k - and most importantly, I have found that the reporting period is associated with some of my key independent variables (in particular, overweight children have shorter reporting periods than normal weight children). So I want to incorporate the different precision of the summary outcome into my regression models. In most linear regression models I would achieve this by weighting each observation by the inverse of the variance of the dependent variable measurement using -aweights-. However, -svy reg - does not support weights. My questions are all due to the fact that I am a casual user of complex survey data. Is this because of a theoretical restriction due to the complex designs? Or is it a mechanical problem that I can somehow circumvent? Or is it possible with Stata, only I am overlooking the solution? thanks, Jeph * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

* * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**st: using weights with -svy- commands***From:*Jeph Herrin <stata@spandrel.net>

**Re: st: using weights with -svy- commands***From:*Stas Kolenikov <skolenik@gmail.com>

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