Speaking Stata: Counting groups, especially panels

Nicholas Cox

Stata Journal, 2007, vol. 7, issue 4, 571-581

Abstract: Counting panels, and more generally groups, is sometimes possible in Stata through a reduction command (e.g., collapse, contract, statsby) that produces a smaller dataset or through a tabulation command. Yet there are also many problems, especially with irregular sets of observations for varying times, that do not yield easily to this approach. This column focuses on techniques for answering such questions while maintaining the same data structure. Especially useful are the Stata commands by: and egen and indicator variables constructed for the purpose. With by: we often exploit the fact that subscripts are defined within group, not within dataset. egen functions are often used to produce group-level statistics. Tagging each group just once ensures that summaries, including counts, are of groups, not individual observations.

Keywords: data management; panels (search for similar items in EconPapers)
Date: 2007
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
http://www.stata-journal.com/article.html?article=dm0033

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:tsj:stataj:v:7:y:2007:i:4:p:571-581

Ordering information: This journal article can be ordered from
http://www.stata-journal.com/subscription.html

Access Statistics for this article

Stata Journal is currently edited by Nicholas J. Cox and Stephen P. Jenkins

More articles in Stata Journal from StataCorp LLC
Bibliographic data for series maintained by Christopher F. Baum () and Lisa Gilmore ().