Similarity Between Anticipated Career Selection And Sds Scores Using The Iachan Index

College Student Journal, March, 1999 by Mark J. Miller, Ernest L. Jr. Cowger

In this study the similarity between anticipated career choice and scores on the Self-Directed Search for high school students were examined. Implications for school counselors are discussed.

John Holland's (1973, 1985) theory of vocational choice has survived nearly 25 years of empirical examination and remains the premier theory in the vocational literature (Camp & Chartrand, 1992). Indeed, Holland's model has become the standard; the number of clones of his theory within the career development marketplace testifies to its usefulness (Johnson, 1987; Tracy & Rounds, 1995).

Holland's (1973, 1985) theory maintains that most people are motivated to seek out work environments which correspond to their dominant personality traits. Both work environments and personality can be categorized into six distinct groups or themes: realistic (R), investigative (I), artistic (A), social (S), enterprising (E), and conventional (C).

Further, Holland (1985) stresses the importance of 3-letter codes to identify both personalities and work environments. For example, a 3-letter code of SAE would indicate a client who resembles most the Social type, followed by progressively fewer resemblances to the Artistic and Enterprising types. Corresponding work environments identified by the SAE code would include such occupations as counselor, school teacher, and speech therapist.

One of the most widely used instruments to assess a client's 3-letter code is the Self Directed Search (SDS; Holland, 1994). The purpose of this study, then, is to determine the degree of similarity between personality type (as measured by the SDS) and students' anticipated occupational environment (i.e., future career choice).

If, indeed, people seek out work environments related to their personalities, then one would expect a relatively high congruence (or similarity) between the two. Congruence, according to Holland (1985), refers to the degree of similarity between an individual's personality types and his or her work environment. The difficulty of quantifying the similarity between two 3-letter Holland codes is at the heart of the issue of measuring congruence (Osipow, 1987). Although several agreement indices have been used in studies on congruence (e.g., Gati, 1985; Kwak & Pulvino, 1982; Swaney & Prediger, 1985; Wiggins & Moody, 1981; Zener & Schnuelle, 1976), the index chosen for this study was the Iachan (1984) index. The Iachan index was chosen because it is the scale to receive the latest endorsement by Holland (1985).

The Iachan Index (L4)

The Iachan method has broad applications both within and out of vocational settings. For example, agreement between husband and wife, or between client and counselor, can be evaluated with the Iachan method (Iachan, 1984).

The Iachan index (M) measures the agreement between two "judges" based on the individual ranking provided by each of the judges. It is desirable to assign more relative importance (weight) to "matches," e.g., IAR-IAR, in the positions corresponding to higher rankings. The specific choice of weights, W=22, 10, 5, 4, 2, 1, is given in Table 1. The M index ranges from 0 to 28. The measure M is computed by adding the weights, one for each letter that appears in both three-letter codes, corresponding to positions where the match occurs. For example, a person's code of SEC which is paired with a parent's code of CEI shows two letters in common, E and C. The C is in positions 3 and 1 (or 1 and 3), with a weight of 4. The E is in positions 2 and 2, with a weight of 5. Therefore, the M index is 9 for this person. To discriminate as much as possible among different configurations, Iachan (1984) used some relatively large weights.

Table 1 Illustrative Weights for Assessing Agreement Between Two Three-Letter Codes for the M Index

                         Summary Code of Parent

                        First    Second   Third
Summary Code of Child   Letter   Letter   Letter

First Letter              22       10       4
Second Letter             10        5       2
Third Letter               4        2       1

Note.--Reproduced from Iachan (1984) by special permission of the author and the publisher, Academic Press, Duluth, Minnesota 55802, c. 1984. Further reproduction is prohibited without the publisher's consent.

Method

Participants

A total of 91 students (40 juniors and 51 seniors) from a regional high school volunteered to take the Self-Directed Search (SDS; Holland, 1994) to assist them in their career plans. Of the 44 males and 47 females who participated, a majority (96%) were white with an average age of 16.8 and an age range between 15 and 19. Most of the participants were in the middle to upper categories of socioeconomic status and planned to attend college after high school graduation. Most of the students completed the SDS in approximately 40 minutes.

Measures

Self-Directed Search. The Self-Directed Search (SDS) Form R (Holland, 1994) build on the features of previous versions of the SDS. The new versions contain expanded norms, revised and updated test items, and simplified directions.