The Predictive Index (PI): Definition, Objectivity, Reliability, Validity, and Demographics

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The Predictive Index measures personality. While some experts define personality differently, the most common definition consists of two conceptually distinct concepts.

Definition of Personality

  • Personality as Reputation. Used this way, the term personality refers to the distinctive and unique impression that one makes on others. This perspective refers to personality from the viewpoint of the observer, and is functionally equivalent to a person’s reputation.
  • Personality as Identity. Used this way, personality refers to the structures inside of a person that are useful in explaining why a person creates a particular impression on others. This is personality from the perspective of the actor, concerned with how a person perceives him or herself, and is functionally equivalent to a person’s identity.

Predictive Index Measurements

Within that definition, the Predictive Index measures four primary and fundamental personality constructs:

  1. Dominance: The degree to which an individual seeks to control his or her environment. Individuals who score high on this dimension are independent, assertive, and self-confident. Individuals who score low on this dimension are agreeable, cooperative, and accommodating.
  2. Extroversion: The degree to which an individual seeks social interaction with other people. Individuals who score high on this dimension are outgoing, persuasive, and socially poised. Individuals who score low on this dimension are serious, introspective, and task-oriented.
  3. Patience: The degree to which an individual seeks consistency and stability in his or her environment. Individuals who score high on this dimension are patient, consistent, and deliberate. Individuals who score low on this dimension are fast-paced, urgent, and intense.
  4. Formality: The degree to which an individual seeks to conform to formal rules and structure. Individuals who score high on this dimension are organized, precise, and self-disciplined. Individuals who score low on this dimension are informal, casual, and uninhibited.

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Secondary Construct Measurements

The Predictive Index also measures two secondary personality constructs, which are derived from a combination of each of the four primary personality constructs described previously:

  1. Decision Making:  Measures how an individual processes information and makes decisions. Individuals who score high on this dimension are objective, logical, and are primarily influenced by facts and data. Individuals who score low on this dimension are subjective, intuitive, and are primarily influenced by feelings and emotions.
  2. Response Level:  Measures an individual’s overall responsiveness to the environment, which is reflected in his or her energy, activity level, and stamina. Individuals who score high on this dimension have an enhanced capacity to sustain activity and tolerate stress over longer periods of time. Individuals who score low on this dimension has less of this capacity.

PI Scoring

The scoring of the PI checklist produces a behavioral pattern with three elements, known as the self, the self-concept, and the synthesis. The self measures a person’s natural, basic, and enduring personality. The self-concept measures the ways in which a person is trying to modify his or her behavior to satisfy perceived environmental demands. Lastly, the synthesis, which is a combination of the self and self-concept, measures the ways in which a person typically behaves in his or her current environment.

About the PI

The Predictive Index personality test has been in widespread commercial use since 1955, with minor revisions to the assessment occurring in 1958, 1963, 1988, and 1992. These minor revisions were undertaken to improve both the PI’s psychometric properties and to ensure that each of the individual items on the assessment conformed to appropriate and contemporary language norms.

The PI is currently used by over 8,000 organizations across a wide variety of industries and company sizes, including 92 companies listed in the Fortune 500. Organizations that use the PI are located in 145 different countries, with approximately 30 percent of PI utilization occurring outside of North America. The client renewal rate is currently more than 90%.

Each year, over 2.5 million people complete PI assessments around the world. The PI is used for a variety of talent management purposes, such as strategic planningtalent acquisition, executive on-boarding, leadership development, succession planning, performance coaching, team building, and organizational culture change among others.

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Objectivity of the PI

The PI measures the personality as identity aspect of personality, and has been developed and validated exclusively for use within occupational and organizational populations. To do this, it employs a scientific methodology similar to other psychological measurement instruments.

Specifically, the PI employs a free-choice (as opposed to forced-choice) response format, in which individuals are presented with two lists of descriptive adjectives, both containing 86 items, and are asked to endorse those that they feel describe them (the self domain), and then those that they feel coincide with how they feel others expect them to behave (the self-concept domain).

Summing across these two domains yields a third implied domain (the synthesis), which can be interpreted as reflecting an employee’s observable behavior in the workplace. The assessment is not timed, generally takes approximately five to ten minutes to complete, and is available in paper-and-pencil, desktop, and Internet formats.

Such methodologies are generally considered to be scientifically objective within the fields of psychology and social science.

Reliability of the PI

As mentioned earlier, reliability refers to the consistency or stability of a measure. If the concept being measured is assumed to be consistent, such as a personality trait, then the measure should yield similar results if the same person responds to it a number of times. If the concept being measured is assumed to be inconsistent, such as mood, then the measure should yield dissimilar results if the same person responds to it a number of times.

One way to estimate reliability is by computing the measure’s test-retest reliability. Test-retest reliability is perhaps the easiest assessment of a measuring device’s reliability to conceptualize and understand. Using the same group of people, a construct is measured at two separate points in time and then the two sets of scores are compared.

This technique yields a correlation often known as the coefficient of stability, because it reflects the stability of test scores over time. If the measure under study is reliable, people will have scores that are similar across trials. Note that the shorter the time interval between administrations of the test (e.g., two weeks versus three months), the higher will be the test-retest coefficient.

The test-retest reliability of the PI was first examined in 1983, 1999, 2009, and 2011. Taken as a whole, the results from these tests indicate that the PI demonstrates acceptable levels of test-retest reliability.

A second way to estimate reliability is by computing the measure’s internal consistency reliability. This is accomplished by determining whether the individual items on the assessment intended to measure the same construct (such as dominance) are mathematically related.

Internal consistency methods estimate the reliability of a test based solely on the number of items within the test and the average intercorrelation among those items. The internal consistency reliability of the PI has been examined in three different studies. The average internal consistency reliability of PI Factors across these studies is .85, with a range of .82 to .87.

Although estimates vary, the lower boundary for the acceptability of internal consistency reliability is often taken as .70. There may also be an upper boundary of acceptability as well, perhaps .90 or above, that may signal measurement redundancy across some of the items.

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Validity of the PI

As previously described, validity refers to the accuracy of a measure. A measure is valid if it actually measures what it purports to measure.

Construct validity is demonstrated when a measure is statistically compared with another measure of similar and/or different concepts. To be successful, the comparison measure must have been soundly constructed and be generally accepted. Such research on the PI has been conducted twice. Both of these studies compared the PI with Raymond Cattell’s 16PF. (The 16PF is a well-respected and well-researched personality assessment.)

A construct validity study involves looking at patterns of correlations. Correlations are mathematical measures that can identify the presence and strength of the relationship between two variables. A pattern should emerge that meets the following expectations: Factors that are defined in a similar way by both the PI and the 16PF should prove to be very similar statistically (e.g., the PI’s extroversion factor and the 16pF’s extroversion factor), and factors that are defined in a dissimilar way on both the PI and the 16PF should prove to be mathematically unrelated (e.g., the PI’s extroversion factor and the 16PF’s emotional stability factor).

In both of these studies, the PI successfully demonstrated construct validity: the relationships you would intuitively expect should be related were mathematically related, and the relationships you would intuitively not expect should be related were mathematically unrelated.

Criterion-related validity is demonstrated when a measure is statistically compared with behaviors it claims to predict. We say that the PI is related to, and can predict, behaviors in the workplace. Criterion-related validity studies objectively show whether these relationships exist, and if so, they show the nature of these relationships.

The PI has been investigated in nearly 500 concurrent (in which data for the predictor and criteria are collected at the same time) and predictive (in which there is some time-lapse between when the data for the predictor and criteria are collected) criterion-related validity studies since September of 1976, for a variety of jobs, in a variety of industries, in a variety of countries, and utilizing a wide range of job performance metrics, such as tenure, turnover, sales, and customer satisfaction.

This body of evidence supports the fact that the PI is indeed consistently related to important workplace outcomes, with studies typically yielding uncorrected correlations between the PI factors and individual job performance criteria in the .20 to .40 range. These correlations indicate that the PI can be an effective predictor of workplace performance.

Demographics of the PI

The U.S. population is increasingly diverse, as are the populations of many other countries. As a result, personnel selection systems that rely solely or primarily on measures of cognitive ability significantly adversely affect most protected groups, especially African Americans, Native Americans, and Hispanics. White people are often hired at a disproportionately high rate when typical cognitive ability tests are the primary selection and screening tools.

These adverse impacts created substantial pressure on companies to find equally valid but less discriminatory selection techniques. Research on personality variables indicates that they have much less, and often no, adverse impact on members of protected groups,’ a tremendous advantage when dealing with increasingly heterogeneous customer, supplier, and employee bases.

PI Worldwide has performed significant research to determine whether the PI discriminates against protected classes. In a report written by Dr. Richard Wolman of Harvard University, the PI was analyzed to determine whether men and women tended to score differently on the PI, and whether African Americans, Hispanics, and Caucasians tended to score differently on the PI. His analyses showed that neither gender nor race was significantly related to the PI scores.

In a more recent study, the PI was analyzed to determine whether the PI produces adverse impact based on age. The study showed that for all PI factors, people over age 40 (the protected class) had PI patterns that were no different than people under age 40, confirming earlier findings.

The Predictive Index has now been translated into 70+ languages and Braille, has been used globally since 1958, and is seeing strong growth in Asia and India over the past 10 years.

PI Worldwide has conducted criterion-related validity studies involving employees from China, Canada, India, Britain, Spain, Portugal, Germany, Hungary, Russia, Australia, and the Netherlands. The results of these international job validity efforts demonstrate the same quantitative connections between the PI and job performance that our U.S.-based studies have shown.

The results of this body of research indicate that the PI is age-, gender- and race-neutral, and that the inclusion of a well-validated personality assessment such as the PI in a company’s personnel selection system may lead to a more demographically diverse workforce. Furthermore, there is no evidence to indicate that the inclusion of the PI in a company’s personnel selection system, either in a compensatory or multiple-hurdle selection model, results in adverse impact against any protected class.

1 Hough, 1. M. (1998). “Personality at Work: Issues and Evidence.” In M. Hakel (Ed.), Beyond Multiple Choice: Evaluating Alternatives to Traditional Testing for Selection (Hillsdale, NJ: Erlbaurn), pp. 131-159.

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Jim Gribble HeadshotAs a Senior Consultant with PI Midlantic, I use Predictive Index to help clients make smart hiring and people management decisions. Don’t risk costly law suits, Predictive Index is not only backed by hundreds of validity studies, it is also EEOC compliant and PI Midlantic is authorized to work with government entities through the GSA (U.S. General Services Administration contract # GS-02F-0099Y)

To introduce you to the Predictive Index, I’d like to invite you to take the assessment yourself. I’m confident you’ll find its results both enlightening and actionable.






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