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| From | Kim Peeters <kimpeeters84@yahoo.com> |
| To | "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |
| Subject | st: How to drop low frequency patterns from panel data |
| Date | Fri, 3 Feb 2012 01:22:57 -0800 (PST) |
Dear Statalist users, I have an unbalanced panel data set. The yearly data spans a period of almost twenty years. However, most subjects only participated in the last years of the study, which is confirmed by the analysis of the different panel patterns using -xtdescribe-. While some patterns' frequency is >1000, other patterns only occur once. To improve the data quality, I would like to drop all patterns that occur less than twenty times. I have not been able to accomplish this. Thus far, I can only re-generate the -xtdescribe- output again. xtpatternvar,gen(pattern) egen tag =tag(ID) tabulate pattern if tag, sort Any advice on how to drop low frequency patterns from panel data? Thank you! Best regards, Kim * * 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/