An extension of Holland’s theory

Describing a university occupation using the position classification inventory: an extension of Holland’s theory

Mark J. Miller

This study examined perceptions of a university-level occupation using the recently developed Position Classification Inventory (PCI). Results suggest that the PCI shows promise as a method of classifying specific occupations according to Holland’s theory.


Perhaps the most widely accepted method for describing occupations is Holland’s theory of people and occupational environments (Holland, 1985, 1997). Holland’s theory can be perceived as a direct attempt to organize and systemize the knowledge of self and, secondarily, as the matching of that self with occupational environments (Slaney, Hall, & Bieschke, 1993). Both occupational environments and personalities are grouped into six major categories: Realistic (R), Investigative (I), Artistic (A), Social (S), Enterprising (E), and Conventional (C).

In Holland’s typology, both personality and environment are expressed in three-letter codes. A three-letter code is formed by selecting, from Holland’s six types, the three types that most closely characterize the person or his or her work-school environment. The three-letter code provides a brief summary of what a person or environment is like by showing the degree of resemblance to three occupational groups. For example, the three-letter code of CER suggests that the person or environment has dominant Conventional aspects but also possesses the Enterprising and Realistic characteristics to a somewhat lesser degree. Extensive descriptions of the six types can be found in Holland (1985).

Two of Holland’s basic notions are that (a) persons in a vocation have similar personalities, and (b) persons tend to choose actual occupational environments consistent with their personality orientations. Finally, a primary assumption behind Holland’s approach is “vocational satisfaction, stability, and achievement depend on the congruence between one’s personality and environment in which one works” (1985, p. 10). It is clear that the validity of Holland’s theory hinges on not only the ability to adequately describe personality types but also to accurately characterize occupational environments. Thus, the more comprehensively specific occupations are studied, the more useful they are likely to be in meeting the need of predicting a favorable match between clients and large numbers of occupations.

One publication often used to assist clients in considering occupations consistent with their personality is the Dictionary of Holland Occupational Codes (DHOC; Gottfredson & Holland, 1996). The DHOC provides a way of classifying most occupations according to Holland’s (1985, 1997) theory. The DHOC, however, does not provide a method of directly assessing any specific position using Holland’s (1985, 1997) personality/environmental typology. The Position Classification Inventory (CPI; Gottfredson & Holland, 1991) was developed, in part, to address this particular shortcoming of the DHOC. The PCI shows promise as a method of classifying occupations according to Holland’s theory (Maurer & Tarulli, 1997).

The most straightforward application of the PCI involves classifying occupations (Gottfredson & Holland, 1991). The purpose of this study, then, is to analyze the degree of congruence between the DHOC’s classification of a specific occupation and one worker’s classification of the same occupation using the PCI. It is assumed that information from this article will provide additional support for the usability and validity of the DHOC in career counseling. Finally, most of the research on Holland’s model has involved students or workers in occupations that require a college degree (Tranberg, Slane, & Ekberg, 1993). The present study included a specific semi-professional occupation: Financial-Aid Counselor.


The second author delivered the PCI to one financial-aid counselor at a medium-size southern university. The financial-aid counselor was female, in her 40’s, earned a master’s degree, had worked on the job for 20 years, and expressed a moderate level of job satisfaction.

Dependent Measures

The Position Classification Inventory (PCI; Gottfredson & Holland, 1991).

The Position Classification Inventory (PCI) was developed to provide a valid, economical method with which to classify any position or occupation according to Holland’s (1985, 1997) typology of work environments. The PCI’s most important use is as an inventory for classifying positions and occupations. It is also helpful for understanding sources of dissatisfaction with a current job.

The PCI is an 84-item inventory in which a job incumbent or supervisor describes the demands, rewards, and opportunities to express or display preferences that an occupation environment provides. Each environmental model is represented by 13 items, for a total of 78 items. Six experimental items are not scored. Typically, the inventory can be completed in 10 minutes or less.

No special instruction or supervision is usually required. The user simply follows directions in the item booklet and records responses on the hand-scored answer sheet. Respondents are encouraged to mark one response for each item.

Alpha (internal consistency reliability) coefficients for the PCI scales range from .74 to .87, with a median of .79. The alpha coefficients for the supervisor’s sample range from .71 to .91, with a median of .83. In writing the initial items and in writing new items for revisions, empirical evidence from the broad literature on the theory (Holland & G.D. Gottfredson, 1990) was attended to, with special attention to occupation analysis data and the theory (G.D. Gottfredson & Holland, 1989). Thus, the PCI appears to have both face and content validity.

Some Research on the PCI

Initial attempts to validate the PCI indicate it is potentially useful for researchers and counselors (Austin, 1993). Maurer and Tarulli (1997) examined the relationship between the environmental dimensions underlying Holland’s theory of vocational choice and skill requirements, context characteristics, and task frequency rating for managerial jobs. The profile of observed correlations was generally consistent with the judges’ expectations based on Holland’s theory, providing support for both the framework and the construct validity of the PCI. Other researchers have used the PCI to investigate how well Holland’s (1985) typology can distinguish among occupational specialties (see Upperman & Church, 1995).

DHOC Classification

The job title of financial-aid counselor was located in the DHOC and a three-letter code of SEC was identified. Specifically, the job description in the DHOC was as follows: Financial-Aid Counselor (education) SEC, DOT 169.267-018.

Scoring of Congruence

Quantifying the degree of similarity between two Holland codes is at the heart of measuring congruence. Much of the research in vocational psychology concentrates on attempts to clarify this similarity (Osipow, 1987).

In his review, Spokane (1985) listed 8 indices of congruence. Later, Camp and Chartrand (1992) compared 13 different measures that had been developed to operationalize Holland’s congruence, however, Brown & Gore, (1994) “may have hit pay dirt” (Holland, 1997, p.16).

Thus, the index chosen for this study was the Brown and Gore (1994) “‘C” (for congruency) index. This “C” index was selected because it (1) is consistent with Holland’s theory, (2) is more comprehensive than other indices, such as Zener and Schnvelle (1976) index, (3) is recommended by Holland (1997), (4) has a normal distribution, (5) is easy to calculate, and (6) is sensitive to code orders.

The Brown and Gore (1994) index (C) is an extension of Holland’s first-letter hexagonal distance measure to a three-letter code. The formula for C=3(x)+2(x)+(x), where x is a score of 3, 2, 1, or 0 assigned to each comparison according to the hexagonal distance between the letters (3= identical letters, 2= adjacent hexagonal letters, 1= alternate hexagonal letters, 0= opposite hexagonal letters).

To illustrate, a person with an ISA code who is in a perfectly congruent (ISA) environment would receive a congruency score (C) of 18, C= [3(3) + 2 (3) + 1(3)] = 18. However, an ISA person in an SAE environment would receive a score of 8, C= [3(1)+ 2(2) + 1(1)1 = 8. C can range from 0 to 18, with higher scores reflecting progressively higher levels of congruence.


The purpose of this study was to examine the degree of congruency between the DHOC’s classification of a specific working class occupation and a worker’s classification of the same occupation using the PCI. Results reveal a moderate congruency score (x = 9) using the Brown & Gore Index (range 0-18).

Upon closer inspection, however, the worker’s PCI classification of CSE contained the identical letters of the DHOC’s classification (i.e., SEC), albeit arranged differently. The dissimilarity between the codes could be explained as slight individual differences in perceptions of job and self. It could be argued that important similarities do indeed exist between the DHOC and the PCI.

The findings of this study provide some additional data in support of Holland’s theory (1985, 1997) and helps explain why his theory of occupations has survived over thirty years of empirical scrutiny and remains the premier theory in vocational literature (Camp & Chartrand, 1992). For example, the authors of the PCI (Gottfredson & Holland, 1991) state that the “PCI has passed enough tests to recommend its use in practical application as a method of assessing positions and occupation” (p.45). The results of this study further reinforce Gottfredson’s and Holland’s assertions.

In conclusion, it appears that both the DHOC and PCI hold promise as tools for understanding semi-professional occupations and for providing realistic occupational information on these types of occupations to college bound clients. Before generalizing the results of this study to similar populations, however, larger sample sizes are needed. In addition, future research in non professional settings will broaden the validity of the PCI (as well as the DHOC).


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Zener, T. B. & Schnelle, L. (1976). Effects of the Self-Directed Search of high school students. Journal of Counseling Psychology, 23, 353-359.


Professor; Counseling


Graduate Student


Associate Professor


Professor, Psychology

Louisiana Tech University

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