I. J. Good (1916 – 2009) was a prolific scientist who contributed to many fields, mostly from a Bayesian standpoint. This column explains his idea of quasi- Bayes (a.k.a. pseudo-Bayes) estimation or smoothing of categorical frequencies in a contingency table, which is especially useful as a...

Stata’s main data model treats observations in rows and variables in columns quite differently, but rowwise problems also arise that require working against the grain. This column shows how to exploit existing functions and egen functions when they exist and apply to such problems. It offers...

The problem of handling Roman numerals in Stata is used to illustrate issues arising in the handling of classification codes in character string form and their numeric equivalents. The solutions include Stata programs and Mata func- tions for conversion from numeric to string and from string to...

Ronald Aylmer Fisher suggested transforming correlations by using the inverse hyperbolic tangent, or atanh function, a device often called Fisher's z transformation. This article reviews that function and its inverse, the hyperbolic tangent, or tanh function, with discussions of their...