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From |
sjsamuels@gmail.com |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Using stratified samples in STATA / giving weights |

Date |
Tue, 8 Sep 2009 12:29:48 -0400 |

Thomas Your knowledge about weights is faulty--weights are usually >1, for an observation's weight is the number of population members represented by the observation (the weight can be non-integer). Weights <1 do arise, but not in the sample that you are describing. Before going any further. I suggest that you read Sharon Lohr. Sampling: Design and Analysis, Duxbury, 1999). Also, look at her section on sample size calculations. The particular sample size calculation will depend on the purpose of your survey--whether descriptive or analytic. If the latter than do not use the finite population correction. If you know a lot of about your population, you can also apply post-stratification techniques. The book "Sampling of Populations" by Levy and Lemeshow (Wiley) has some Stata examples, although they are limited to descriptive samples. Regards, -Steve On Sat, Sep 5, 2009 at 11:26 AM, Thomas Klausch<thomas.klausch@gmail.com> wrote: > Dear list members, > > I am planning to survey a stratified sample from a relatively small finite > population of which I know the size. I am not too familiar with weighting > techniques and the STATA -svy- command family, which is why I write. Maybe > somebody can give useful advice. > > My popluation consists of size n=8800, with n=900 and n=7900 sized relevant > stratas. I decided to sample n=600 from each of the STRATAs since I am > particularly interested in estimates from the smaller strata. > > My knowledge about weighting tells me that this gives rise to weights of > approx. .20 for the small strata and approx. 1.80 for the large strata. In > SPSS I would know how to use the weights function, as there is only one. > STATA provides several weight options -fweight-, -pweight-, -aweight- and > -iweight-. I have tested in STATA that it gives the same estimates using > -iweight- than SPSS does using the WEIGHT BY command. > > My first question is if -iweight- is reasonable to use for my case when > estimating regression models (in particular logistic panel models). > My second question is whether there is a, maybe better, way to use the > options provided in the -svy- command family to specify the survey design. > maybe there is also a third way I do not know of. > > If anybody could give advice or further reference for detailed information > on -svy- I'd appreciate it a lot. > > Many thanks > > Thomas > > * > * 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/ > -- Steven Samuels sjsamuels@gmail.com 18 Cantine's Island Saugerties NY 12477 USA 845-246-0774 * * 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/

**Follow-Ups**:**Re: st: Using stratified samples in STATA / giving weights***From:*sjsamuels@gmail.com

**References**:**st: Using stratified samples in STATA / giving weights***From:*Thomas Klausch <thomas.klausch@gmail.com>

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