Update October 2023: I think the best compilation of critical evaluation of the HEXACO model can be found in the Special Issue of European Journal of Personality. It includes a target article about the HEXACO followed by a long peer commentary section.
https://onlinelibrary.wiley.com/doi/10.1002/per.2284
In particular, several of the open commentaries are quite critical of the HEXACO. See in particular
De Raad & Mlačić:
Ashton and Lee (2020a) declare their belief in HEXACO as the optimal model of traits. They fail, however, to deliver a coherent line of reasoning, use detailed side-issues to tackle big problems, are relaxed about giving true facts and fare by examples, instead of systematic studies. We point at different issues, such as the rhetorical style, the untimeliness of settling for HEXACO, and the consequences this would have. Last, we emphasize the importance of cross-cultural studies.
De Young
Under the guise of combatting objections to the HEXACO model, the target article argues that HEXACO should replace the Big Five as the preferred taxonomy of personality traits in personality psychology. However, it fails to invalidate several important reasons why one might prefer the Big Five. These include limitations of lexical data, evidence from non-lexical studies, the fact that the Big Five can encompass content related to honesty and humility within Agreeableness, and consideration of explanatory theory rather than prediction by specific instruments.
Lylam, Crowe, Vize, & Miller
We see little benefit to separating Honesty-Humility from the broader FFM Agreeableness domain. In our commentary, we summarize several studies showing that although lexically based Big Five measures under-represent H-H content, the same cannot be said for FFM-based measures. We also indicate that contrary to claims by some ad- vocates, FFM-based Agreeableness is more strongly related to the Dark Triad than H-H. Finally, we review a recent study examining the lower-order structure of FFM Agreeableness that failed to reveal a separate H-H factor, despite more than adequate representation of that content.
McCrae
The HEXACO model is based on lexical studies that suggest six factors, including an independent Honesty-Humility factor. I argue that natural languages are imperfect maps of objective reality, and that a pattern of evidence from other catalogs of traits favors the Five-Factor Model (FFM). I reinterpret Ashton and Lee (2019) to mean that HEXACO H and A are aspects of the FFM A factor. Traits related to Honesty-Humility ought to be included in comprehensive personality measures, and optimal assessment will include a wide range of facet-level traits.
Ones, Dilchert, Giordano, Stanek, Viswesvaran
The HEXACO personality model does not provide an accurate organization of the personality domain: it over-relies on lexical research, focuses on one level of the personality hierarchy, and lacks coherent theory. The HEXACO personality inventory overemphasizes internal consistency, factorial homogeneity, and unidimensionality; lacks construct coverage and has construct validity problems.
Schwaba & Hopwood
Although the HEXACO model offers some specific advantages over the Big Five, both suffer from limitations common to universal, broad-bandwidth models of personality structure. The precedence of the Big Five means that past research and meta-analyses have been organized around this model, and we believe that this inertia will con- tinue to favor the Big Five as the paradigmatic structural model into the near future. To overcome this inertia, the next paradigm shift in personality psychology will likely need to address problems common to the HEXACO and Big Five.
Viswesvaran & Ones
Since 1940s the construct of honesty, referred to as integrity in the industrial-organizational psychology literature, has been widely researched amassing hundreds of research stud- ies demonstrating the utility of the construct in prediction and explanation (Ones, Viswesvaran, & Schmidt, 1993, 2012; Viswesvaran & Ones, 2016). All studies to date also indicate that the construct assessed by integrity tests is a compound of conscientiousness, agreeableness, and emotional stability, in that order (see Ones, 1993; Ones & Viswesvaran, 2001 for summaries).
.... the theoretical rationale and empirical evidence for the superiority of the HEXACO and its Honesty-Humility factor are insuffi- cient.
Watson & Clark
They highlight how Big Five and HEXACO extraversion differ and its impliations:
We examine the HEXACO Extraversion domain in relation to that of the five-factor model of personality (FFM). Although the HEXACO-PI-R Social Self-Esteem facet scale correlates substantially with FFM indicators of extraversion, it has an even stronger (negative) association with the neuroticism facet of depression and, therefore, seems to represent the opposite end of that dimension. Consequently, neuroticism-related content is spread across three domains (Emotionality, Agreeableness, Extraversion) in the HEXACO model. We discuss implications of this pattern for understanding relations between traits and internalizing forms of psychopathology, such as depression.
Widiger et al
The predominant dimensional model of personality structure is provided by the Five-Factor Model (FFM). The HEXACO is presented as a possible alternative, but it has not been adopted by many researchers. One concern with respect to the HEXACO is that it has essentially elevated two facets of agreeableness to the level of a broad do- main. Honesty and humility are best understood as facets of agreeableness.
Original Answer: We had a discussion of the pros and cons of the HEXACO model in a recent article that draws on arguments and evidence presented by the "heavyweights" of the Big 5 (Anglim, & O'Connor, 2019).
Here is the quote of the paragraph that focusses specifically on the critiques:
Although the HEXACO model is receiving growing support, the necessity
of a sixth broad trait, as well as the nature of this trait are
subjects of current debate.
- First, other prominent six factor
inventories including the Hogan Personality Inventory (Hogan & Hogan,
1992), the Six Factor Personality Questionnaire (Jackson, Paunonen, &
Tremblay, 2000), and Saucier's Big Six (Saucier, 2009) have not
converged on the same sixth factor in the same way that has broadly
occurred with the Big Five (De Raad, Barelds, Mlačić, et al., 2010).
- Second, while several lexical studies have broadly supported the
HEXACO model, the support is far from universal.
- Third, Saucier and
Ostendorf (1999) have argued that any broad trait in addition to the
Big Five will correlate highly with one of the existing Big Five, and
honesty-humility correlates relatively highly with agreeableness (r =
.67 in Gaughan, Miller, & Lynam, 2012). Honesty-humility also
correlates reasonably well with straightforwardness and modesty facets
of agreeableness in the NEO-PI-R, suggesting that a comprehensive
facet-level model using the Big Five may provide similar predictive
benefits (Costa & McCrae, 1995; Gaughan et al., 2012).
- Fourth,
Barford, Zhao, and Smillie (2015) mapped the Big Five and HEXACO
traits to a common space provided by the interpersonal circumplex, and
found that honesty-humility occupied a fairly similar space to the
politeness aspect of B5 agreeableness.
- Finally, Condon (2017) assessed
the covariance structure of approximately 700 statement-based
personality test items drawn from the most commonly used public-domain
personality measures (including an approximately equal representation
of items from prominent five and six-factor measures). While he found
support for a large number of narrow traits, factor analysis suggested
five broad traits, and when six factors were extracted, the sixth
factor did not correspond to honesty-humility.
References:
- Anglim, J., & O'Connor, P. (2019). Measurement and Research Using the Big Five, HEXACO, and Narrow Traits: A Primer for Researchers and Practitioners. Australian Journal of Psychology, 71, 16-25. https://psyarxiv.com/a78g2/download