ثبات و تغییر در منافع: بررسی طولی رتبه 7 از طریق کالج  Stability and change in interests: A longitudinal examination of grades 7 through college

nstruments The Personal Global Inventory–Short (PGI–S). Personal Globe Inventory-Short (PGI-S) (Tracey, 2010) was a shortened version of the original PGI (Tracey, 2002b) using the item response theory. Participants were asked to respond to 40 unique items, with respect to both the degree of liking ranging from 1 (strongly dislike very much) to 7 (strongly like very much) and the degree of competence ranging from 1 (unable to do) to 7 (able to do very much). Sample items are “Seat patrons at a restaurant” and “Install electrical wiring”. The PGI-S allows for multiple scales of interest. It primarily measures interests in eight basic interest types on the plane defined by the dimensions of People/Things and Ideas/Data (i.e., Social Facilitating, Managing, Business Detail, Data Processing, Mechanical, Natural/Outdoors, Artistic, and Helping), as well as two interest types located at the opposite ends of the dimension of Prestige (i.e., High prestige and Low prestige). It also enables the generation of scores for the RIASEC types. In this study, we only focused on the six RIASEC types and the dimensional scores of People/Things, Data/Ideas, and Prestige. Derived Measures Profile Crystallization. The circumplex model of interest has been theorized (Holland, 1997) and demonstrated to fit RIASEC scares (Rounds & Tracey, 1996; Tracey & Rounds, 1995; Tracey & Rounds, 1993). This model specifies that six RIASEC scales are arranged on a circular structure by their relative similarities (e.g., R is most similar to I and C, less similar to A and E, and least similar to S). Prediger (1982) and Prediger and Vansickle (1992) proposed a two-dimension structure of Things/People and Data/Ideas to characterize dimensions underlying the RIASEC circular. Specifically Things/People was calculated as (2*R+I –A – 2*S – E+C) and Data/Ideas was calculated as (1.73*E + 1.73*C- 1.73*I – 1.73*A). High values of Things/People thus indicate an endorsement of things over people and negative scores indicate an endorsement of people over things. High scores on Data/Ideas were indicative of data endorsement while negative scores represented Ideas. Given this structure, an individual RIASEC profile could be represented by two dimensional scores. Interest crystallization was operationalized by using a length score generated from the two dimensional scores of Things/People and Data/Ideas. Given that the RIASEC profile can be said to exist in a circular structure represented by Things/People and Data/Ideas, the distance between the origin with the point in the circle located by two dimensional scores represents the circular variance (Mardia, 2014). This length score provides an index of the clarity or crystallization of the RIASEC profile. Such indices have been used in interest (Tracey et al., 2005) and personality (Wiggins, Phillips, & Trapnell, 1989) measures as a means of representing differentiation in a circular structure.