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| From | "Poliquin, Christopher" <cpoliquin@hbs.edu> |
| To | "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |
| Subject | st: Removing (partial) duplicate obs with lots of vars |
| Date | Wed, 20 Oct 2010 15:30:32 -0400 |
Hello, I have a dataset with about 73,000 observations and close to 400 variables. The observations are companies and their actively trading issues in a given year. Some of these 73,000 observations are duplicates, but none of the observations actually match on all variables, so I am faced with the problem of which observation to drop. Does anyone have a suggestion of how to compare the duplicate observations, consolidate the information each has in certain variables, and then keep one observations? For example, consider the following... +--------------------------------------------------------------------------------+ KEY CUSIP EXCHANGE YEAR RATIO NOTES 011 03467110 NYSE 2007 Name change --> Acme Corp. in 2005 011 03467110 2007 011 03467110 NYSE 2007 1:2 +--------------------------------------------------------------------------------+ So, let's say I label these duplicates because it is the same company and issue in the same year. What I now need is one observation in my dataset that looks like this... +--------------------------------------------------------------------------------+ KEY CUSIP EXCHANGE YEAR RATIO NOTES 011 03467110 NYSE 2007 1:2 Name change --> Acme Corp. in 2005 +--------------------------------------------------------------------------------+ As I said, the dataset is 73,000 obs and 400 vars. Minimizing typing *and* minimizing errors/data loss is very important. I would greatly appreciate anyone's advice/help. Best wishes, Chris * * 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/