Abstract
Purpose and Nature of Test
The Vocational Preference Inventory (VPI), 1985 revision, is a self-administered, brief paper–pencil, personality-interest inventory developed to “yield a broad range of information about interests, interpersonal relationships, values, self-conceptions, coping behaviors, and identifications” (Holland, 1985, p. 1). The VPI is designed for use with individuals with normal intelligence ages 14 through adult. The test consists of a list of 160 occupations which people indicate they are interested in by marking “Yes” and are disinterested in by marking “No.” The test takes approximately 15 to 30 min to complete and score, according to the manual. The author cautions that the VPI should be “interpreted only in combination with other psychosocial information such as age, sex, educational level, field of training, and current occupational status” (p. 1).
Although originally developed as a brief personality test, the VPI is primarily used as a way of assessing vocational interests. The test is based on Holland’s six dimension model of vocational personalities: Realistic, Investigative, Artistic, Social, Enterprising, and Conventional (RIASEC; Holland, 1966). The typology codes are compatible with use of Holland’s The Occupations Finder (1996) and the Dictionary of Holland Occupational Codes (Gottfredson & Holland, 1996).
Practical Applications
The VPI is a user-friendly, quick, and cost-efficient way of gathering information on work style, work typology, and interest in specific occupations. Test materials include the manual with directions for administration, scale and profile interpretation instructions and technical information, as well as a test booklet/answer sheet/profile combination form. Instructions for administration and scoring are straightforward and objective. Issues regarding reading level required, appropriateness of use with individuals with disabilities, or individuals who use English as a second language are not discussed in the manual.
Scoring is easily accomplished by peeling away the top page of the self-scoring, carbonless Answer Sheet and counting the number of blackened circles in rows that correspond to Scales 1 to 9. Scale 10 (Infrequency) is scored by counting the number of blackened circles in two columns, and Scale 11 (Acquiescence) is scored by counting the number of Yes responses for Items 1 to 30. The scorer can then transfer the raw scores to the back page of the Answer Sheet to derive the T-scores (M = 50, SD = 10) for both male and female profiles.
According to the manual, nearly anyone can administer and score the VPI, but it cautions that interpretation should be performed only by those who have at least 1 year of graduate training in a vocationally oriented field. Those looking to interpret the VPI should have a good understanding of psychometric testing, occupational theories, and how personality can influence career choice. Users should familiarize themselves with the manual and related research, and are also encouraged to administer the test to “a few people well known to the user” (Holland, 1985, p. 5). The manual contains simple and brief instructions on profile interpretation, a number of example profiles, and a section on how to use the profiles to inform career and personal assessment.
The test taker’s responses are used to generate scores on 11 scales, 6 of which are described as interest scales. The Realistic (R) Scale measures the extent to which the test taker has traits related to “realism, practicality, masculinity, and conventionality” (Holland, 1985, p. 6). High scorers on the Investigative (I) Scale are described as “bright, scholarly, and persistent” (p. 7). The Artistic Scale (A) measures traits thought to characterize “artistic” persons, such as originality, a good imagination, unconventionality, and introversion. The Social (S) Scale reflects traits such as “sociability, femininity, passivity, problem solving by means of feelings rather than thinking” and high scorers typically have “the ability to relate to others, or the ability to form ‘close’ as opposed to ‘superficial’ relationships” (p. 7). The Enterprising (E) Scale measures traits associated with “dominance, risk taking, sociability, and enthusiasm” (p. 8). The Conventional (C) Scale measures a person’s tendency for “conformity, a whole-hearted uncritical acceptance of cultural values and attitudes, and living in the eyes of others with its emphasis on self-control” (p. 8). High scorers tend to be “generally productive and effective in well-structured tasks” (p. 8).
The remaining five scales gather information outside the RIASEC model. The Self-Control (Sc) Scale measures a person’s ability to control impulses. The Masculinity–Femininity (Mf) Scale measures how closely a person identifies with traditional masculine and feminine career interests. This scale can also be used as an indicator of faking, because this scale should correlate closely with similar interest scales, such as S and A. The Status (St) Scale reflects the test taker’s “self-esteem and concern for prestige and power” and is a general measure of self-esteem and self-confidence (Holland, 1985, p. 9). The Infrequency Scale is described as both a social desirability scale and as a measure of traits and attitudes such as “self-deprecation, incompetency, socially undesirable traits, and a history of personal and vocational failure” (p. 9). The lower the score on this scale, the more personally effective the person is thought to be. Finally, the Acquiescence (Ac) Scale’s primary purpose is to “detect dissimulation and extreme response biases which may go undetected in forced-choice and true-false formats” (p. 9).
Technical Aspects
The VPI has undergone eight revisions since its original publication in 1953. The most recent revision (1985) was not a substantial overhaul of the 1977 version, but instead included a number of minor changes meant to more easily allow translation of occupational codes to specific occupational titles, to increase low response rates by females to some occupational titles, and to increase scale homogeneity (Holland, 1985). The 1985 version included a limited number of new studies that added to construct and criterion-related validity evidence. Evidence regarding reliability remained the same as in the 1977 version. The normative data focused on high school students, 2- and 4-year college students, employed men and women, African Americans, American Indians, and other groups are the same as in the sixth revision (1968) manual.
In general, the interest scales have been shown to have concurrent and/or predictive validity comparable with other interest inventories, such as the Self-Directed Search (SDS; Holland, 1994). As the other scales are not comparable with other interest inventories, only evidence for construct validity for them has been established. The most recent studies cited in the manual that provide evidence for the validity of the VPI are nearly 20 years old, and a considerable amount of the overall validity evidence is more than 30 years old. The authors recommend an updated manual that includes recent evidence regarding the validity of the 1985 revision.
Evidence for reliability is similarly out of date. The internal consistency (KR 20) statistics for the 1977 revision are provided in the 1985 revision manual, and they indicate that most of the scales are relatively homogeneous (range = .85–.91; Holland, 1985). Scales that have a more heterogeneous variety of occupations, such as Mf, St, and I, have lower internal consistency statistics (range = .42–.62; Holland, 1985). Data regarding the test–retest reliability are taken from the sixth revision (1968) and indicate that the VPI has moderate to high reliability. At a 3-month interval, retest reliabilities for the interest scales ranged from .54 to .80 for samples of junior college students. The sample consisted of 62 men and 53 women (Holland, 1968).
Conclusion
The VPI is a brief, self-administered personality-interest inventory developed for use with individuals ages 14 through adult. Strengths of this instrument include ease of administration, scoring, and interpretation. The test provides helpful information regarding vocational interests, and the test has a strong theoretical base (Holland, 1966). Information from the test is easily translated to specific occupations using Holland’s The Occupations Finder (1996) and the Dictionary of Holland Occupational Codes (Gottfredson & Holland, 1996). However, due to the dated nature of the normative, reliability, and validity studies (Shepard, 2012), caution must be exercised when interpreting the results, especially with persons of underrepresented status. Despite attempts in the 1985 revision to reduce sexist language and increase low female response rates to some occupational titles, the VPI still relies on traditional gender roles to categorize vocational interests. Furthermore, the labor force has seen some dramatic changes since the VPI 1985 revision resulting in the creation of new occupations that are not reflected in the scales. Given these caveats, the VPI 1985 revision is still relevant and useful as a tool for career counseling and vocational exploration based on work styles, work typology, and occupational interests, particularly when used in combination with other instruments or resources which promote exploration and discussion (Rounds, 2012).