Handbook for the Sixteen Personality Factor Questionnaire (16PF): In Clinical, Educational, Industrial, and Research Psychology

The handbook's central argument is that the 16PF's sixteen primary factors are not arbitrary scale labels but empirically derived source traits—the fundamental, causally efficacious dimensions underlying surface behavior. Cattell, Eber, and Tatsuoka reject the criterion-keying approach to questionnaire construction, in which items are selected solely for their empirical correlation with an external outcome. Instead, the handbook presents the 16PF as the product of a multi-decade factor-analytic program that began with the full lexicon of personality descriptors and cross-validated findings across self-report, objective test, and life-record data. The manual's interpretive sections consistently subordinate practical profile reading to this theoretical foundation, insisting that users understand what the factors are before asking what a given score means.

The handbook presents the primaries as the primary level of description and the second-order factors as useful but derivative summaries. Cattell consistently argued that the sixteen primary traits are the real structural units of personality, while the broader factors—Extraversion, Anxiety, Tough-Mindedness, Independence, and Self-Control—are convenient higher-order aggregations. This position put him at odds with Eysenck, who treated three broad dimensions as fundamental. The 16PF Fifth Edition technical manual later formalized five 'global factors' that closely resemble the Big Five, but the 1970 handbook's emphasis remains on the interpretive richness and causal specificity of the sixteen primaries, which Cattell believed captured distinctions lost in broader dimensional schemes .

The most persistent criticism concerns scale homogeneity and reliability. Cattell claimed that the 16PF scales were deliberately heterogeneous—designed to capture broad source traits rather than narrow response sets—and that conventional internal-consistency estimates therefore underestimated their true reliability. Subsequent research challenged this defense. A review by Kline and associates found no evidence that the scales were deliberately heterogeneous and reported that conventional reliability estimates closely matched alternate-form coefficients, with factors L, M, and N performing particularly poorly . Blinkhorn's doctoral work similarly found the heterogeneity claim statistically invalid for most scales . The handbook itself reports split-half reliabilities that are moderate for single forms and higher only when Forms A and B are combined, acknowledging the instrument's limitations for individual prediction .

The 16PF's sixteen primaries have been shown to map substantially onto the five broad dimensions that became the Big Five consensus. The 16PF Fifth Edition technical manual explicitly reports five global factors—Extraversion, Anxiety, Tough-Mindedness, Independence, and Self-Control—that correspond closely to the Big Five domains . Cattell's collaborator Gregory Boyle and others argued that this convergence validates the 16PF's structural coverage while preserving the primaries as useful lower-order facets. However, the handbook's implicit claim that sixteen factors are necessary for adequate description has not been widely accepted; most contemporary researchers treat the Big Five or HEXACO as sufficient at the broad level. The 16PF remains valuable precisely for its facet-level detail, but its status as the definitive structural taxonomy has diminished.

The Handbook is a technical and interpretive manual, not a theoretical treatise. Its primary audience is practitioners—clinicians, educators, industrial psychologists—who administer and interpret the 16PF and need norms, reliability and validity data, and guidance on profile interpretation. The bulk of its 388 pages consists of normative tables, occupational and clinical profile comparisons, and factor-by-factor interpretive guidance. Personality and Mood by Questionnaire (1973), by contrast, is Cattell's theoretical justification for treating questionnaires as instruments for testing personality theory, with extended discussion of the Q-data tripod and the philosophy of factor-analytic measurement. The Handbook assumes the theoretical framework and gets to work applying it; the later book argues for the framework itself.

The handbook supplies profile comparisons for twenty-five occupational groups and five clinical syndromes—schizophrenics, manic-depressives, neurotics, psychopaths, and convicts—allowing users to compare an individual's 16PF profile against established group patterns . These norms were a significant practical innovation, enabling the 16PF to be used for personnel selection and clinical screening in ways that raw factor scores could not support. However, the norms are historically and culturally bounded: they derive from mid-twentieth-century American samples and should not be applied uncritically to other populations without local validation. The handbook itself cautions that profile matching is probabilistic, not diagnostic. Later editions of the 16PF replaced and expanded these norms substantially, and contemporary users should consult current technical manuals rather than relying on the 1970 tables.