Truthfulness Scale

There are many terms that address the notion of truthfulness within the context of assessment, treatment and rehabilitation, including denial, problem minimization, misrepresentation and equivocation. The prevalence of denial among patients and offenders is extensively discussed in the psychological literature (Marshall, Thornton, Marshall, Fernandez, & Mann, 2001; Brake & Shannon, 1997; Barbaree, 1991; Schlank & Shaw, 1996). The impact the Truthfulness Scale score has on other scales or test scores is contingent upon the severity of denial or untruthfulness. In assessment, socially desirable responding impacts assessment results when respondents attempt to portray themselves in an overly favorable light (Blanchett, Robinson, Alksnis & Sarin, 1997).

Truthfulness Scale awareness increased with the release of the Minnesota Multiphasic Personality Inventory (MMPI), arguably one of the most widely used personality tests in the United States. Soon thereafter, socially-desirable responding was demonstrated to impact assessment results (Stoeber, 2001; McBurney, 1994; Alexander, Somerfield & Ensminger, 1993; Paulhus, 1991). Truthfulness Scale conceptualization began in earnest with the idea of self-response accuracy. Test users want to be sure that respondents’ self-report answers are truthful or accurate. Evaluators and assessors need to know if they can rely upon the reported test data being accurate. In other words, can the respondent’s (patient or offender’s) self-report answers be trusted? Research shows that truthfulness is also an important factor in diagnosis, treatment effectiveness and recidivism.

Client (patient or offender) truthfulness has been associated with more positive treatment outcomes (Barber, et. al., 2001). Denial often accompanies lack of accountability, lack of motivation to change, resistance and general uncooperativeness (Simpson 2004). Problem minimization has also been linked to lack of treatment progress (Murphy & Baxter, 1997); treatment dropout (Daly & Peloski, 2000; Evans, Libo & Hser, 2009); and offender recidivism (Nunes, Hanson, Firestone, Moulden, Greenberg & Bradford, 2007; Kropp, Hart, Webster & Eaves, 1995; Grann & Wedin, 2002). Some researchers have suggested that client denial should be eliminated prior to commencing treatment. Denial reduction methods include use of survivor reports, directed group work, or addressing cognitive distortions that may cause denial (Schneider & Wright, 2004).

Invariably, assessors (evaluators, test users) must answer the questions, Was the client (patient, offender) truthful while being tested? Can we rely on the test results? Evidence-based truthfulness scales answer these questions.

The "interview" has been the mainstay in evaluations for many years despite its paradoxical lack of reliability, validity and accuracy. Most mental health professionals agree that the interview has not been a good predictive instrument, and that it is notoriously time consuming. Most practitioners believe the interview by itself does not present a defensible basis for making diagnostic and treatment decisions. Interviews are prone to error and the reasons are many, owing to diversity in interviewer personalities and in training and equivocal motivation. Interviewers must repeat, paraphrase and probe for scoreable answers, thereby introducing subjectivity and error.


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