qfactor: A command for Q-methodology analysis

In this article, I introduce qfactor, a new command for Q-methodology analysis. Q-methodology is a combination of qualitative and quantitative techniques for studying subjectivity. Its quantitative component is based on a by person factor analysis, usually followed by a factor-rotation technique. Currently, only a handful of programs with limited capability are available for Q-methodology analysis, and none of them are in the major commercial statistical programs such as Stata, SPSS, and SAS. qfactor offers an attractive set of options, including different factor-extraction and factor-rotation techniques in Stata. The use of qfactor is illustrated using a dataset representing 40 individuals' perceptions on marijuana legalization.