Haslam, N., Holland, E., and Kuppens, P. (2012). “Categories versus dimensions in personality and psychopathology: A quantitative review of taxometric research.” Psychological Medicine, 42(5), 903-920.
Reviews 177 articles reporting 311 taxometric findings from a combined 533,377 participants, asking whether psychological variables are categorical (types) or dimensional (continua). Raw findings were 38.9% taxonic; after correcting for methodological weaknesses the authors estimate the true prevalence of taxonic findings at 14%. They conclude that most latent variables in personality and clinical psychology are dimensional, and that many early taxonic findings are likely spurious.
The main evidence for measuring TIME orientation as continuous scores and against assigning people to four types. It also explains the instability of MBTI-style labels near their cut points: cutting a continuum into categories produces reclassification when scores move slightly.