João Pedro Azevedo

João Pedro Azevedo

Chief Statistician @ UNICEF | Development Economist

GROUPFUNCTION

High-performance data aggregation for large datasets — several orders of magnitude faster than Stata's collapse — computing means, sums, variances, first values, minima, and maxima across groups in a single pass.

SSC Stata SSC GitHub Issues

Installation

Stata ssc install groupfunction

Description

groupfunction replaces several collapse functions (mean, sum, variance, first, max, min). The command is several orders of magnitude faster than Stata’s built-in collapse command, making it particularly useful for large datasets.

Examples

* Basic usage: mean and min by group
sysuse auto, clear
groupfunction [aw=weight], mean(price) min(weight) by(foreign)

Citation

Corral, P., Nguyen, M.C. and Azevedo, J.P. “GROUPFUNCTION: Stata module to replace several basic collapse functions.” Statistical Software Components S458475, Boston College Department of Economics.