Survey data analysis in stata jeff pitblado associate director, statistical software statacorp lp 2009 canadian stata users group meeting outline 1 types of data 2 2 survey data characteristics 4. These four weights are frequency weights fweight or frequency, analytic. How to apply survey weights in stata for the european working. Logistic regression based solutions if case level population. Note that not all commands recognize all types of weights.
An audience member informed me that stata software provides four definitions of weight variables, as follows. At the 2007 joint statistical meetings in denver, i discussed weighted statistical graphics for two kinds of statistical weights. Basically, by adding a frequency weight, you are telling stata that a single line represents observations for multiple people. If you use the svyset command, the weight that you specify must be a. A weight of 2 means that the case counts in the dataset as two identical cases. These adjustments do not alter the coefficients but they do alter the standard errors, usually in. This video is part iii in the series on sampling and weighting in the demographic and health surveys dhs.
When we say we want the mean and standard deviation of a variable with probability weights, what we most likely. Details depend, of course, on the specific research questions your are trying to answer and the nature of your data. You can find a nice summary of these different options here, as well as information on the more specialized option iweight. Clarification on analytic weights with linear regression. What types of weights do sas, stata and spss support. How to understand weight variables in statistical analyses.
Demonstration of how to weight dhs data in stata youtube. Weighting is part of the departmental of methodology software tutorials sponsored by a grant from the lse annual fund. Analytic weights observations as if each observation is a mean computed from a sample of size n, where n is the weight variable. How do i generate weight variable in stata stack overflow. How to apply survey weights in stata for the european. Stata assumes that with aweights, the scale of the weights does not matter. Thus, if the spread of the group means stays the same as weight increases, then sigma must be increasing. There are several kinds of weight variables in statistics.
The first time around the loop, i is set to 1, and stata summarizes the response using weight for observations with values of group equal to 1. The manual entry for r summarize tells us that to calculate medians we need to specify the detail option and that the median is left behind in memory in rp50. Stata analysis tools weighted least squares regression. I was just asking about the balanced panel because most dare i say all estimators implemented in stata handle unbalanced panels. This is the first article of the series of publications in the human ecology journal on biostatistics using stata software. In spss i simply click on weight by the sampleweight variable but in stata i was using svyset pweightsampleweight. You often find this type of weight in complex survey data.
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