The simple practice effects commonly observed when retaking general cognitive ability tests present a potential paradox. If observed score changes reflect real changes in g, we must revisit our understanding of its stability. Conversely, if observed score changes reflect something other than a true change in the underlying latent construct, this…

It is argued that the statements and accusations made by Stephen Jay Gould about the use of factor analysis are incorrect and unjustified and that tests properly designed for the purpose can adequately measure a "general" or "g" factor of intelligence, particularly in view of the developments in testing since "The…