Watts, Simon and Paul Stenner (in press). Q methodology: The inverted factor technique. Irish Journal of Psychology.
Abstract: This paper aims to re-establish the legitimacy of the inverted factor technique in psychology, to provide details of appropriate data collection and analytic processes, and to highlight some possible applications of the method. The inverted (or by-person) factor technique had traditionally been applied to the same matrix of data that supported more conventional (by-item) factor analyses. But this is statistically problematic. In fact, the same data matrix can properly be inverted or transposed (and thus factor analyzed by both row and column) only when a single measuring unit is present throughout the matrix. This condition is rarely satisfied. As a consequence, the inverted technique all but disappeared from psychology. This paper will nonetheless demonstrate, by detailed reference to William Stephenson�s �Q methodology�, that inverted or by-person factor analyses are both viable and statistically legitimate as long as a different (and specialist) matrix of data is collected and analyzed. It is hoped that psychologists will now be encouraged to explore the potential of the inverted technique.