ONESPELL: Stata module to generate single longest spell for each unit in panel data, listwise
Christopher F Baum
onespell produces a subset of a panel data set in which all observations on varlist are non-missing and contiguous in the time dimension. If a panel unit contains more than one such subset, the longest "spell" is retained. Although performing this operation for a single variable of interest is fairly straightforward, this routine deals with a more challenging task: generating the single longest spell in a listwise fashion, across a set of variables. This applies the same logic as does, e.g., regress: an observation with a missing value in any variable will be deleted from the regression sample. Some matrix software (e.g., DPD for Ox) requires that panel data be organized in this fashion, with each unit appearing as a single contiguous block of non-missing observations. onespell will produce such a dataset, which after conversion to Stata version 6 format (by, e.g., Stat/Transfer) may be read directly by Ox. The routine has been tested with the latest version of Ox (3.40) and the DPD package (1.21). The routine makes use of N.J. Cox's -tsspell-.
In order to set up a list of libraries that you have access to,
you must first login
or sign up.
Then set up a personal list of libraries from your profile page by
clicking on your user name at the top right of any screen.