I’ve just finished reading a recently published book called The Cult of Personality, by Annie Murphy Paul, which presents a scathing criticism of the use of personality testing in a variety of settings, including the workplace. The book provides some interesting information, particularly regarding the lives of the authors of some of these tests. According to The Cult of Personality, for example, Isabel Myers, the author of the famous Myers-Briggs test, had no formal training in psychology or test construction. The man who developed the Rorschach Inkblot Test, Hermann Rorschach, may have died of heartbreak from the failure of his test to gain wide acceptance. You will also learn that Starke Hathaway, the creator of the MMPI, sometimes wore shoes that didn’t match and frequently came to classes with grease stains on his clothing. Beyond such trivia, The Cult of Personality raises a number of important questions regarding the use of such tests in a wide variety of settings, including the workplace. In the remainder of this column, I will address several of the author’s critical assumptions about personality tests. Some of these criticisms are implicit and some are explicit. Because I am trained in Industrial Psychology, I will review the book only in terms of the use of personality tests for hiring and selecting employees. I leave the use of personality tests in other venues (e.g., clinical therapy, academic settings, and teambuilding efforts) to others. Specifically, I will address four critical assumptions made in this book. Assumption #1: Personality tests do not predict job performance. To determine whether a test is useful, industrial psychologists rely heavily on “criterion-related validity” studies. To conduct such a study, industrial psychologists typically administer the test to a large number of current employees and then correlate their test scores with some measure of job performance (e.g., a supervisor’s ratings). A correlation coefficient is then calculated between the test scores and job performance. A correlation coefficient ranges between zero and one: a zero indicates there is no relationship between the test and job performance, while a one indicates that there is a perfect relationship between the test and job performance. Because human beings are rather unpredictable, it is nearly impossible to find a correlation that is much higher than .50. Generally speaking, a useful test correlates somewhere between .30 to .50 with job performance. For many years, academic researchers were skeptical of the predictive validity of personality tests in the workplace. This skepticism is generally traced to a critical review article that appeared in the 1960s, which severely criticized the use of personality tests for selecting employees. In the 1990s, however, two developments led to a major reconsideration of the use of personality tests. First, using a technique called meta-analysis to review and summarize hundreds of previous studies, researchers concluded that personality tests did have some, albeit limited, predictive validity in the workplace. Sorting the research based on the “big five” theory of personality, which assumes that personality consists of five dimensions (i.e., openness to new experience, conscientiousness, extraversion, emotional stability, and agreeableness), researchers found that scores on conscientiousness modestly correlated with job performance. A second development, beginning around the 1980s, was the construction of specialized personality tests. The most well-known example, which received a mention in The Cult of Personality, was the paper-and-pencil honesty or integrity test. Studies of these tests were also eventually subjected to a meta-analysis, which concluded that integrity tests correlated with a broad array of workplace behaviors, including counterproductive activities and general job performance. Hence, there is solid scientific evidence that some personality dimensions do in fact predict job performance to some extent. Nonetheless, combining invalid scales with valid scales (e.g., conscientiousness) to predict job performance may actually reduce the predictive power of the valid tests. The bottom line here is, as with many things in life, personality testing brings value in selection if used appropriately, responsibly, and in an informed manner. Assumption #2: There are better ways to select people for jobs than to use personality tests. While The Cult of Personality does little to address alternative procedures, we ourselves need to consider the alternative to these kinds of tests. One potential alternative is other kinds of tests. Cognitive ability tests, for example, might be used, but they too have weaknesses. One limitation of cognitive ability tests is that they too tend to be far from perfect predictors of job performance, with predictive validities falling somewhere between .30 to .50. A second weakness is that they tend to produce disparate impact, which makes companies that use them susceptible to discrimination charges. Other tests, such as assessment centers, are expensive to develop and use, and also are far from being perfect predictors of future job performance. A second potential alternative is to rely more heavily on interviews. But interviews are far from perfect predictors and they may be fraught with biases and subjectivity. Even a well-designed, scientifically based interview is not a perfect predictor of job performance. Interviews have one more limitation: while a relatively inexpensive test might be administered to large numbers of applicants, few companies are willing to interview hundreds of candidates to weed out the poor ones. Thus for positions where there are many applicants, a personality test might be an effective first step to reducing the pool to a more manageable number. Assumption #3: A large number of honest people fail integrity tests. Another major criticism mentioned in The Cult of Personality is that some tests, such as integrity tests, have an extremely high false positive rate (i.e., a large number of presumably honest people fail integrity tests). In a careful scientific review of these tests published in 1989, two scientists observed that, overall, 40% to 70% of people passed these tests. While research does suggest that there is a high false positive rate, the criterion (theft on the job) is difficult to track and detect. Thus, the high false positive rate may have less to do with a poor test than with a poor criterion (i.e., theft on the job). Such tests do also show a modest degree of predictive validity, using criteria such as performance ratings and even theft on the job. The more contemporary “integrity tests” of today measure a broader scope of behaviors. These are often referred to as “tests of conscientiousness.” While they indirectly predict dishonesty, these tests evaluate “work values” such as showing up to work on time, following rules, taking responsibility for getting work completed, and risk-taking on the job. Finally, in predicting theft on the job, employers have few good alternatives, and even those alternatives (e.g., criminal record checks; references) have serious shortcomings. Despite some weaknesses, then, honesty tests, and in particular tests of conscientiousness, may be useful in industries where there are many more applicants than companies can possibly hire. Indeed, very few companies can hire every candidate that applies and there has to be some basis for rejecting applicants. Assumption #4: Job applicants have few legal rights when it comes to personality tests. In terms of legal rights, I believe it all depends on your perspective. There are three major potential protections for job applicants, and the author mentions all three of them. First, job applicants are provided protection under the Civil Rights Act of 1964 and 1991 from racial, gender, and other related types of discrimination. Such lawsuits may rely on the disparate impact theory of discrimination, in which the differential impact of such tests can be used as evidence of discrimination. Second, some states have privacy laws that may pertain, and lawsuits have been successfully filed under these statutes. Finally, the Americans with Disabilities Act (ADA) may provide some protection for job applicants from the use of certain tests such as the MMPI. In a recent lawsuit (Karraker v. Rent-A-Center, 2004) filed against a company using the MMPI for selection, however, the court ruled that its use did not constitute a medical test and therefore the company did not violate the ADA. From an applicant perspective, these and other laws may be seen as insufficient protection from the arbitrary use of personality tests. From a company’s perspective, on the other hand, such laws may be seen as a potential deterrent in using personality tests. Conclusion and Suggestions The uncritical use of personality tests in the workplace is foolish at best, and at worst, may be costly to companies. If you are either currently using personality tests, or considering the use of these tests for hiring and selection decisions, here are some suggestions:
- Make sure the personality test is properly validated.
- Review the test for possible legal problems, including potential disparate impact, possible privacy violations, ADA concerns, and other legal violations.
- Review all test items so you are sure they are not offensive or leave a negative impression with job candidates.
- Make sure you clearly understand how to use the results of the personality test. Contrary to the achievement tests that most of us are commonly exposed to, higher scores are not always better scores. Some jobs may require employees who score low on the attributes measured by these tests.
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