Taxometrics, polytomous constructs, and the comparison curve fit index: A Monte Carlo analysis.

The taxometric method effectively distinguishes between dimensional (1-class) and taxonic (2-class) latent structure, but there is virtually no information on how it responds to polytomous (3-class) latent structure. A Monte Carlo analysis showed that the mean comparison curve fit index (CCFI; Ruscio, Haslam, & Ruscio, 2006) obtained with 3 taxometric procedures—mean above minus below a cut (MAMBAC), maximum covariance (MAXCOV), and latent mode factor analysis (L-Mode)—accurately identified 1-class (dimensional) and 2-class (taxonic) samples and produced taxonic results when applied to 3-class (polytomous) samples. From these results it is concluded that using the simulated data curve approach and averaging across procedures is an effective way of distinguishing between dimensional (1-class) and categorical (2 or more classes) latent structure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Does attention-deficit/hyperactivity disorder have a dimensional latent structure? A taxometric analysis.

An understanding of the latent structure of attention-deficit/hyperactivity disorder (ADHD) is essential for developing causal models of this disorder. Although some researchers have presumed that ADHD is dimensional and others have assumed that it is taxonic, there has been relatively little research directly examining the latent structure of ADHD. The authors conducted a set of taxometric analyses using data from the NICHD Study of Early Child Care and Youth Development (ns between 667 and 1,078). The results revealed a dimensional latent structure across a variety of different analyses and sets of indicators for inattention, hyperactivity/impulsivity, and ADHD. Furthermore, analyses of correlations with associated features indicated that dimensional models demonstrated stronger validity coefficients with these criterion measures than dichotomous models. These findings jibe with recent research on the genetic basis of ADHD and with contemporary models of ADHD. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Malingering as a categorical or dimensional construct: The latent structure of feigned psychopathology as measured by the SIRS and MMPI-2.

The 6 nonoverlapping primary scales of the Structured Interview of Reported Symptoms (SIRS) were subjected to taxometric analysis in a group of 1,211 criminal and civil examinees in order to investigate the latent structure of feigned psychopathology. Both taxometric procedures used in this study, mean above minus below a cut (MAMBAC) and maximum covariance (MAXCOV), produced dimensional results. A subgroup of participants (n = 711) with valid Minnesota Multiphasic Personality Inventory-2 (MMPI-2) protocols were included in a second round of analyses in which the 6 nonoverlapping primary scales of the SIRS and the Infrequency (F), Infrequency-Psychopathology (Fp), and Dissimulation (Ds) scales of the MMPI-2 served as indicators. Again, the results were more consistent with dimensional latent structure than with taxonic latent structure. On the basis of these findings, it is concluded that feigned psychopathology forms a dimension (levels of fabrication or exaggeration) rather than a taxon (malingering-honest dichotomy) and that malingering is a quantitative distinction rather than a qualitative one. The theoretical and clinical practice implications of these findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detecting small taxa using simulated comparison data: A reanalysis of Beach, Amir, and Bau's (2005) data.

On the basis of taxometric analyses of data sets that they created to pose interpretive challenges, S. R. H. Beach, N. Amir, and J. J. Bau (2005) cautioned that using comparison data simulated by J. Ruscio's programs can lead to inaccurate conclusions. Careful examination of S. R. H. Beach et al.'s methods and results plus reanalysis of their data fails to substantiate this concern: Using comparison data identified the taxonic structure of S. R. H. Beach et al.'s data sets, even when the taxon base rate was very low. The authors show that J. Ruscio's simulation programs generate comparison data appropriately and that analyzing these data provides a useful interpretive aid. Additionally, the authors discuss and illustrate the effective use of the inchworm consistency test to disambiguate taxometric results for small taxa and dimensional constructs with positively skewed indicators. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What is the latent structure of alcohol use disorders? A taxometric analysis of the Personality Assessment Inventory Alcohol Problems Scale in male and female prison inmates.

Three indicators derived from the Personality Assessment Inventory (PAI) Alcohol Problems scale (ALC)—tolerance/high consumption, loss of control, and negative social and psychological consequences—were subjected to taxometric analysis—mean above minus below a cut (MAMBAC), maximum covariance (MAXCOV), and latent mode factor analysis (L-Mode)—in 1,374 federal prison inmates (905 males, 469 females). Whereas the total sample yielded ambiguous results, the male subsample produced dimensional results, and the female subsample produced taxonic results. Interpreting these findings in light of previous taxometric research on alcohol abuse and dependence it is speculated that while alcohol use disorders may be taxonic in female offenders, they are probably both taxonic and dimensional in male offenders. Two models of male alcohol use disorder in males are considered, one in which the diagnostic features are categorical and the severity of symptomatology is dimensional, and one in which some diagnostic features (e.g., withdrawal) are taxonic and other features (e.g., social problems) are dimensional. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Revisiting the latent structure of eating disorders: Taxometric analyses with nonbehavioral indicators.

Researchers have debated whether clinical eating disorders are best conceptualized as one extreme along a continuum of degree or as qualitatively different from less severe eating disturbances. Taxometric analysis, a set of procedures that assess the structure of a given disorder by detecting whether a latent taxon exists among its indicators, has just begun to be applied to eating disorder research. Its application to this domain may clarify whether eating disorders best conform to a dimensional (i.e.. continuum) or taxonic model. The latent structure of eating disorders was examined in a sample of 532 college women by using 2 popular taxometric procedures (i.e., maximum covariance analysis and latent mode analysis) with 5 nonbehavioral indicators of eating disorder symptomatology. Results across procedures suggest that the data are more indicative of a dimensional solution, as no latent taxon was uncovered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bootstraps taxometrics: Solving the classification problem in psychopathology.

Classification in psychopathology is a problem in applied mathematics; it answers the empirical question "Is the latent structure of these phenotypic indicator correlations taxonic (categories) or nontaxonic (dimensions, factors)?" It is not a matter of convention or preference. The taxometric procedures, MAMBAC and MAXCOV-HITMAX, provide independent tests of the taxonic conjecture and satisfactorily accurate estimates of the taxon base rate, the latent means, and the valid and false-positive rates achievable by various Cuts. The method requires no gold standard criterion, applying crude fallible diagnostic "criteria" only in the phase of discovery to identify plausible candidate indicators. Confidence in the inference to taxonic structure and numerical accuracy of latent values is provided by multiple consistency tests, hence the term coherent cut kinetics for the general approach. Further revision of diagnostic systems should be based on taxometric analysis rather than on committee decisions based on clinical impressions and nontaxometric research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Taxometric and factor analytic models of anxiety sensitivity: Integrating approaches to latent structural research.

This study represents an effort to better understand the latent structure of anxiety sensitivity (AS), as indexed by the 16-item Anxiety Sensitivity Index (ASI; S. Reiss, R. A. Peterson, M. Gursky, & R. J. McNally, 1986), by using taxometric and factor-analytic approaches in an integrative manner. Taxometric analyses indicated that AS has a taxonic latent class structure (i.e., a dichotomous latent class structure) in a large sample of North American adults (N = 2,515). As predicted, confirmatory factor analyses indicated that a multidimensional 3-factor model of AS provided a good fit for the AS complement class (normative or low-risk form) but not the AS taxon class (high-risk form). Exploratory factor analytic results suggested that the AS taxon may demonstrate a unique, unidimensional factor solution, though there are alternative indications that it may be characterized by a 2-factor solution. Findings suggest that the latent structural nature of AS can be conceptualized as a taxonic latent class structure composed of 2 types or forms of AS, each of these forms characterized by its own unique latent continuity and dimensional structure. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

On the nature of nicotine addiction: A taxometric analysis.

Taxometric procedures were used to determine whether nicotine addiction is best conceptualized as a dimensional or a categorical (i.e., taxonic) phenomenon. Using data from the 2003 National Survey on Drug Use and Health (NSDUH; N = 12,467), results from MAMBAC, MAXEIG, and LMODE taxometric analyses provided strong evidence that nicotine addiction has a taxonic latent structure. Members of the addiction taxon, which constituted approximately 48% of those who reported smoking in the past 30 days, consumed a higher number of cigarettes per day, had stronger craving, higher levels of nicotine tolerance, more inflexible smoking patterns, and shorter latencies to smoking their first cigarette on waking compared with nontaxon members. These findings of a distinct addiction taxonic structure were replicated using a 2002 NSDUH sample (N = 12,224). Finally, the predictive validity of the taxon variable was compared with a continuous indicator sum. The taxon accounted for most of the predictive variance in the indicator sum, but the latter generally showed significant predictive power even after controlling for the former. Thus, these smoking variables may have both a categorical and a dimensional structure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Latent structure of the alexithymia construct: A taxometric investigation.

Despite a wealth of research on the validity of alexithymia and its association with a number of common medical and psychiatric disorders, the fundamental question of whether alexithymia is best conceptualized as a dimensional or categorical construct remains unresolved. In the current investigation, taxometric analysis is used to examine the nature of the latent structure of alexithymia. Several nonredundant taxometric procedures were performed with item sets from the 20-item Toronto Alexithymia Scale (R. M. Bagby, J. D. A. Parker, & G. J. Taylor, 1994) as indicators. These procedures were applied separately in large community (n = 1,933) and undergraduate (n = 1,948) samples and in a smaller sample of psychiatric outpatients (n = 302). The results across various taxometric procedures and the different samples provide strong support that alexithymia is a dimensional construct. Some theoretical implications of these findings for research on the alexithymia construct are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

To sum or not to sum: Taxometric analysis with ordered categorical assessment items.

Meehl's taxometric method has been shown to differentiate between categorical and dimensional data, but there are many ways to implement taxometric procedures. When analyzing the ordered categorical data typically provided by assessment instruments, summing items to form input indicators has been a popular practice for more than 20 years. A Monte Carlo study compared the accuracy of taxometric analyses implemented in the traditional way (without summing items) and taxometric analyses implemented with the summed-input method. These analyses generated no support for the summed-input method, which substantially reduced discriminating power for 2 of the 3 procedures studied. Accuracy was highest when 5 or more indicators and 4 or more ordered categories were used. Findings from the simulation study were then used to help interpret the results for taxometric analyses of antisocial personality disorder criteria with real research data. In this example, the traditional method yielded clearer results than the summed-input method. Implications for the use and further study of the taxometric method in assessment research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Taxometric Analysis of Psychopathic Personality.

Although a common assumption throughout much of the professional and popular literature is that psychopaths are qualitatively different from others, very few studies have examined the latent structure of psychopathy. Whether psychopathy is a discrete category or a continuous dimension may have implications for research on the assessment, etiology, and treatment of this disorder. This study examined the latent structure of psychopathy in a sample of 309 jail and prison inmates. Three taxometric procedures were used to analyze indicators drawn from the Psychopathic Personality Inventory (S. O. Lilienfeld & B. P. Andrews, 1996), a self-report instrument. Consistent with prior studies that used other measures of psychopathy, none of the analyses was consistent with a taxonic solution, suggesting that psychopathic personality may be best understood as existing on a continuum. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The latent structure of dietary restraint, body dissatisfaction, and drive for thinness: A series of taxometric analyses.

Although the latent structure of various eating disorders has been explored in previous studies, no published studies have examined the latent structure of theoretically relevant variables that have been shown to cut across eating disorder diagnoses. The current study examined 3 such variables (dietary restraint, body dissatisfaction, and drive for thinness) among undergraduate women using the taxometric method. The 5 items from the Eating Disorders Examination Questionnaire's Dietary Restraint subscale were used as dietary restraint indicators, whereas items from the Eating Disorders Inventory Body Dissatisfaction and Drive for Thinness subscales were used as indicators of body dissatisfaction and drive for thinness, respectively. As hypothesized, MAXCOV (maximum covariance) and MAMBAC (mean above minus below a cut) analyses suggested that all 3 variables are dimensional; therefore, individuals with high levels of reported dietary restraint, body dissatisfaction, and drive for thinness appear to differ in degree, but not in kind, from those with lower levels. Implications for prevention, assessment, classification, and treatment are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The taxonicity of schizotypy: A replication.

P. E. Meehl's model (1962, 1990) of schizotypy and the development of schizophrenia implies that the structure of liability for schizophrenia is dichotomous, hypothesizing that a "schizogene" determines one's membership in a latent class (or taxon; P. E. Meehl & R. R. Golden, 1982). The present study sought to replicate earlier findings concerning the taxonic latent structure and general population base rate of schizotypy (M. F. Lenzenweger & L. Korfine, 1992). P. E. Meehl's (1973; P. E. Meehl & R. R. Golden, 1982) MAXCOV-HITMAX taxometric analytic procedures were applied to a subset of items from the Perceptual Aberration Scale (PAS; L. J. Chapman, J. P. Chapman, & M. L. Raulin, 1978), a prominent psychometric index of schizotypy, derived from a new randomly ascertained nonclinical university sample (N?=?1,646). Consistent with the authors' previous results as well as Meehl's conjectures, the data strongly suggest that schizotypy, as assessed by the PAS, is taxonic at the latent level with a low general population taxon base rate (i.e.,     

Confirming the latent structure and base rate of schizotypy: A taxometric analysis.

P. E. Meehl's (1962, 1990) model of schizotypy and the development of schizophrenia implies that the structure of liability for schizophrenia is dichotomous and that a "schizogene" determines membership in a latent class, or taxon (Meehl and R. R. Golden, 1982). The authors sought to determine the latent structure and base rate of schizotypy. They applied Meehl's (1973) MAXCOV-HITMAX taxometric analytic procedures to a subset of items from the Perceptual Aberration Scale (PAS; L. J. Chapman et al, 1978), a prominent psychometric index of schizotypy, derived from a randomly ascertained nonclinical sample (N?=?1,093). The results, in accordance with Meehl's conjectures, strongly suggest that schizotypy, as assessed by the PAS, is taxonic at the latent level with a general population taxon base rate of approximately .10. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The latent structure of analogue depression: Should the Beck Depression Inventory be used to classify groups?

Research on depression is often conducted with analogue samples that have been divided into depressed and nondepressed groups using a cutoff score on the Beck Depression Inventory (BDI). Although the relative merits of different cut scores are frequently debated, no study has yet determined whether the use of any cut score is valid, that is, whether the latent structure of BDI depression is categorical or dimensional in analogue samples. The BDI responses of 2,260 college students were submitted to 3 taxometric procedures whose results were compared with those of simulated data sets with equivalent parameters. Analyses provided converging evidence for the dimensionality of analogue depression, arguing against the use of the BDI to classify analogue participants into groups. Analyses also illustrated the notable impact of pronounced skew on taxometric results and the value of using simulated comparison data as an interpretive aid. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differentiating categorical and dimensional data with taxometric analysis: Are two variables better than none?

Taxometric analyses have proven helpful for distinguishing categorical and dimensional data. Many taxometric procedures require at least 3 variables for analysis. What if a construct is defined by only 2 conceptually nonredundant characteristics or a data set contains only 2 empirically nonredundant variables? In Study 1, we performed extensive simulations to determine whether informative results can be obtained when only 2 variables are available for taxometric analysis. The mean above minus below a cut (MAMBAC) and maximum slope (MAXSLOPE) procedures, used with parallel analyses of comparison data, successfully differentiated categorical and dimensional structure. With just 2 variables, it seems especially important that indicators vary across as many distinct values as possible and that investigators obtain as large a sample as possible. Additional findings address questions about the most effective way to implement taxometric analyses. In Study 2, the potential utility of 2-variable taxometric analysis is illustrated using data on proactive and reactive childhood aggression, where the results provided strong support for dimensional structure. As long as high-quality data are available, it appears that one can have confidence in the results of taxometric analyses performed with only 2 variables. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A taxometric study of the Adult Attachment Interview.

This study is the first to examine the latent structure of individual differences reflected in the Adult Attachment Interview (AAI; C. George, N. Kaplan, & M. Main, 1985), a commonly used and well-validated measure designed to assess an adult's current state of mind regarding childhood experiences with caregivers. P. E. Meehl's (1995) taxometric methods (i.e., MAXCOV-HITMAX) were applied to data from 504 AAIs. Analyses revealed that the variation underlying secure versus dismissing states of mind was more consistent with a dimensional than a taxonic model. (Taxometric analyses of preoccupation were indeterminate.) In addition, variation in secure adults' (n = 278) reports about their early experiences revealed little evidence for qualitative groups of earned- and continuous-secures. Rather, the inferred life experiences of secure adults appeared to be distributed continuously. Findings are discussed in terms of their theoretical implications regarding the phenomenon of earned-security specifically and variation underlying secure and insecure states of mind more generally. The consequences of these analyses for AAI reliability training and coding are also explored. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is marital discord taxonic and can taxonic status be assessed reliably? Results from a national, representative sample of married couples.

Addressing potential weaknesses in an earlier investigation, the authors examined the latent structure of marital discord using 4 product indicators from the Marital Satisfaction Inventory-Revised (Snyder, 1997) in a representative sample of community couples (N = 1,020). Results from 3 taxometric procedures suggested that marital discord is taxonic, with an estimated base rate of .31. Cut scores for classifying members of this marital discord taxon were identified. Additional analyses with several data sets of community and clinic couples provided evidence that the marital discord taxon classification demonstrated good (a) 6-week test-retest reliability, (b) criterion validity (i.e., differences in taxon prevalence in community vs. clinic couples), and (c) construct validity (i.e., correlations with therapist ratings of relationship quality). These results suggest that discordant couples differ qualitatively and not just quantitatively from nondiscordant couples and that user friendly methods, suitable for a range of research and clinical applications, can be used to identify marital discord. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The latent structure of life-course-persistent antisocial behavior: Is Moffitt's developmental taxonomy a true taxonomy?

Objective: The purpose of this study was to determine whether life-course-persistent (LCP) and adolescence-limited (AL) antisocial behavior form distinct categories or lie along a common dimension. Method: Taxometric analyses were performed on 2,175 men and women from the National Longitudinal Survey of Youth–Child Data (Center for Human Resource Research, 2009) with at least 1 self-reported delinquent act. The 3 externalizing factor scales from the parent-rated Behavior Problems Index (Peterson & Zill, 1986)—Antisocial, Headstrong, and Hyperactive—served as indicators in an investigation into the latent structure of LCP and AL antisocial behavior. Results: All 3 taxometric procedures included in this study—mean above minus below a cut, maximum covariance, and latent mode factor analysis—produced results consistent with the conclusion that the latent structure of LCP and AL antisocial behavior is dimensional in nature. Conclusion: From a conceptual standpoint, the results of this study suggest that LCP and AL antisocial behavior differ in degree (quantitative difference) rather than in kind (qualitative difference). These results have potentially important implications for theory development as well as for clinical assessment, diagnosis, and intervention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)