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From |
Austin Nichols <austinnichols@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: pweight, aweight, and survey data |

Date |
Thu, 8 Apr 2010 14:52:34 -0400 |

John Westbury <jrwestbury@gmail.com> : pweights and aweights yield the same point estimates but typically different variance (SE) estimates; have you read the help files and documentation available in Stata on weights? e.g. [U] 20.18.3 Sampling weights Sampling weights—probability weights or pweights—refer to probability-weighted random samples. Actually, what you specify in [pweight=...] is a variable recording the number of subjects in the full population that the sampled observation in your data represents. That is, an observation that had probability 1/3 of being included in your sample has pweight 3. Some researchers have used aweights with this kind of data. If they do, they are probably making a mistake. Consider the regression model ... On Thu, Apr 8, 2010 at 1:42 PM, John Westbury <jrwestbury@gmail.com> wrote: > Howdy. > > I am using a data set generated from a complex sample design. > Sampling weights are established to account for the probability of > selection in the sampling design and when applied to records produce a > nationally representative sample. Each record in the sample is for > individuals. > > I have experimented obtaining summary statistics with stata weight > designators of pweight and aweight. Both pweight and aweight > designations for my weight variable yield exactly the same summary > statistics for my data but the definition of pweight and aweight seem > to differ greatly in stata documentation. Can someone clarify why > pweight and aweight yield the same summary statistics? When would > using pweight or aweight generate different results? > > thanks much > John * * 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: pweight, aweight, and survey data***From:*John Westbury <jrwestbury@gmail.com>

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