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From | R G <rghertner@yahoo.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | st: Correctly setting FPC in svyset |
Date | Wed, 9 Feb 2011 03:44:15 -0800 (PST) |
Hello, I'm analyzing a census I've done of schools, no stratification or clustering. Response rate is around 50%. I need to set the FPC (finite population correction) in svyset and I'm not sure the appropriate number to use. I know some argue that there's no need to set the FPC, but in my case the issues I'm surveying on there is a strong case for considering a finite population, and not a superpopulation. According to Stata help: fpc(varname) requests a finite population correction for the variance estimates. If varname has values less than or equal to 1, it is interpreted as a stratum sampling rate f_h = n_h/N_h, where n_h = number of units sampled from stratum h and N_h = total number of units in the population belonging to stratum h. If varname has values greater than or equal to n_h, it is interpreted as containing N_h. It is an error for varname to have values between 1 and n_h or to have a mixture of sampling rates and stratus sizes. The UCLA page also states that: Stata will calculate the actual fpc for us; we just need to specify the population total. (Source: http://www.ats.ucla.edu/stat/stata/seminars/svy_stata_8/Stata_svy_seminar_sampling.htm) If there are a total of 1000 schools, with 500 responses, am I correct in interpreting that I should set the fpc=1000? Just need to confirm this, as I'm relatively new at Stata's svy commands. Thanks Robin * * 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/