International Personality Item Pool – Johnson (IPIP-J)

Abstract

The International Personality Item Pool – Johnson (IPIP-J) is a concise, 120-item measure developed by John A. Johnson and published in 2000. It was specifically designed to assess the thirty facets underlying the Big Five Traits of personality in adults. The IPIP-J serves as a crucial response to the need for a time-efficient, non-proprietary alternative to longer, copyrighted personality instruments, thereby eliminating financial barriers and reducing participant fatigue often associated with comprehensive assessments like the IPIP-NEO. As a component of the broader International Personality Item Pool, the IPIP-J offers a freely accessible and psychometrically sound tool for research applications, including areas such as personnel selection and psychopathic personality traits.

Keywords

Big Five, Five Factor Model, International Personality Item Pool, IPIP-J, short form inventory, personality assessment, psychometrics, John A. Johnson, 120-item measure.

Authors

John A. Johnson.

Purpose

The primary purpose of the IPIP-J was to offer researchers a public domain, time-efficient inventory capable of measuring the full spectrum of the Five Factor Model (FFM) facets (30 facets). This development addressed significant constraints in psychological research where progress in FFM theory was often hampered by the limited availability of measures due to prohibitive copyright restrictions and the pay-to-use nature of established tests, which created substantial financial barriers (Maples et al., 2014).

While the earlier 300-item IPIP-NEO provided a freely available and highly comprehensive assessment, its length proved prohibitive in research settings constrained by time or budget. Furthermore, administering such a lengthy instrument often led to significant participant fatigue, particularly when a battery of assessments was required (Maples et al, 2014; Johnson, 2014). The IPIP-J, therefore, provides a necessary short-form instrument that maximizes efficiency and accessibility while maintaining fidelity to the 30-facet structure of the FFM.

Construct

The IPIP-J measures the thirty specific facets that underpin the five broad domains of the Big Five Traits (Neuroticism, Extraversion, Openness to Experience, Agreeableness, and Conscientiousness). This comprehensive structure is aligned with the Five Factor Model (FFM), a dominant framework in personality psychology.

The development of the IPIP-J was based on the comprehensive item pool of the IPIP-NEO, which initially used 10 items for each of the 30 FFM facets. Through a rigorous reduction process, the IPIP-J utilizes four highly representative items for each of these thirty facets, resulting in a total of 120 items. This structure ensures detailed resolution across the personality dimensions while drastically reducing the time required for administration.

Validity

The validity of the IPIP-J was primarily established by examining its convergence with the well-regarded proprietary instrument, the NEO-PI-R. The IPIP-J was tested for correlations against the IPIP-NEO, which itself was designed as a public domain representation of the NEO-PI-R structure (Maples et al., 2014).

Psychometric studies demonstrated that convergence between the IPIP-J scores and the NEO-PI-R was reasonably good, yielding a correlation coefficient (r) of 0.66 (Maples et al., 2014). This correlation supports the instrument’s ability to capture the intended personality constructs effectively, despite its significant reduction in item count compared to the original comprehensive measures.

Reliability

The internal consistency of the IPIP-J facet scales was evaluated using Cronbach’s Alpha (α). Across the facets, the IPIP-J demonstrated reasonably good reliability, with a reported average α of 0.68 (Maples et al., 2014).

In the scale’s development, Johnson (2014) calculated alphas for both domain and facet scales separately by sex. While the conventional psychometric standard often suggests an alpha of 0.7 as a rule of thumb, all scales achieved a coefficient of at least 0.6. This level of internal consistency was considered acceptable and adequate for four-item scales during the developmental stage of the research, recognizing the necessary trade-off between maximizing reliability and achieving brevity.

Factor Analysis and Development Methodology

The development of the IPIP-J scales was fundamentally rooted in the established FFM factor structure represented by the IPIP-NEO. The methodology employed by Johnson (2014) was a systematic, three-step reduction process designed to optimize the psychometric properties of the resulting 120-item inventory:

1. The process began by applying the reliability calculation function within SPSS to the IPIP-NEO data. This step generated corrected item-total correlations for the 10 original items within each facet scale. Items with the lowest correlation were iteratively removed until precisely four items remained, ensuring that only the strongest indicators of the facet were retained.
2. Secondly, a rational-intuitive strategy was implemented. Johnson meticulously reviewed the remaining items to identify and address potential issues. This included checking for near-duplicates, verifying the items’ fidelity to the original NEO-PI-R structure, and scrutinizing any reference to disability or content that could pose legal concerns, particularly if the scale were utilized for sensitive applications like personnel selection.
3. Finally, Cronbach’s alpha coefficients were computed separately for both the domain and facet scales, stratified by sex, to confirm the resulting structure’s reliability and consistency, thereby validating the scale’s representation of the underlying FFM factors.

Instrument

Test Type: Personality Inventory (Public Domain)

Format: 120-item short-form questionnaire. The inventory consists of 30 facet scales, each measured by 4 items.

Language Available: English (Original development language; available for translation under the broad IPIP guidelines).

Population Group: Adults

Age Group: Adult population

Population Details: The scale was developed using a large online sample comprising 21,588 adults. The author did not provide specific geographical details regarding the majority origin of the respondents (Johnson, 2014).

Test Methodology: Self-report measure. The instrument is intended for efficient administration in research settings, available through the International Personality Item Pool website.

Keywords

120-item measure, short inventory, personnel selection, psychometric development, free access, public domain, internal consistency, participant fatigue.

Authors

Author ORCID Identifier: N/A (Information not provided in source content)

Affiliation Email addresses: N/A (Information not provided in source content)

Correspondence Address: N/A (Information not provided in source content)

Permissions & Fee and Test Year

The IPIP-J is a contribution to the International Personality Item Pool (IPIP), an initiative dedicated to creating a pool of free personality items. Consequently, the scale is in the public domain. No permission or fee is required for its use in research, educational, or commercial applications, fulfilling the original goal of removing financial barriers to personality research.

The scale was initially developed by John A. Johnson and published in October 2000. However, the definitive psychometric validation and methodology detailed in the source content largely stem from the 2014 publication (Johnson, 2014), which solidified the 120-item version.

Reference’s

• Johnson, J. A. (2014). Measuring thirty facets of the Five Factor Model with a 120-item public domain inventory: Development of the IPIP-NEO-120. Journal of Research in Personality, 51, 78-89.

• Maples, J. L., Guan, L., Carter, N. T., & Miller, J. D. (2014). A test of the International Personality Item Pool representation of the Revised NEO Personality Inventory and development of a 120-item IPIP-based measure of the five-factor model. Psychological assessment, 26(4), 1070.

Items of the International Personality Item Pool – Johnson (IPIP-J)

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

The specific 120 items comprising the IPIP-J were not provided in the source content. However, the scale is structured to include four items for each of the 30 facets of the Five Factor Model (FFM), derived through a rigorous item reduction process from the longer IPIP-NEO inventory.