Construct Validity: Relationship of the COPS-P Interest Inventory to Similar Instruments

Correlations of inventories such as the COPS-P with other similar inventories provides information concerning the construct validity of the assessments. This technique is especially useful when developing and implementing new and/or alternative instruments. In the case of the COPS-P, which is an alternate form of the COPS Interest Inventory (COPS, Knapp & Knapp-Lee, 2015), correlations with the COPS clusters are useful in understanding the nature of the COPS-P scales. Correlations between the COPS Interest Inventory and the COPS-P are presented in the table below based on 153 college students.

Correlations between the conceptually similar scales of the COPS-P and the COPS range from .37 to .81 with a median correlation of .65. The correlations were highest between conceptually similar scales. For example, the COPS-P Science, Medical Life and Physical scales were most highly correlated with the COPS Science, Professional and Skilled clusters. This trend was evident for all the COPS-P to COPS scale correlations. The only conceptually similar scales that did not correlate as highly as expected were the COPS Service, Skilled cluster with the COPS-P Service clusters. However, this is not surprising as the COPS-P is used by college students that have self-selected out of all the occupations within the Service, Skilled cluster.

As might be expected in every instance the COPS-P scale is more highly related to the corresponding COPS Professional level scale than the Skilled level scales. The correlations between all the conceptually similar scales provide evidence that supports the validity of the two instruments.

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Technical Supplement June 2019.  

Norms for the COPSystem VIA Assessments

Norms for the COPSystem VIA are based on data gathered from 2015 through 2018 for a sample of 32,638 sixth through twelfth grade educational levels. The National sample was aggregated based on a weighted population of subjects from four geographic regions of the U.S. identified by the 2010 U.S. Census Report. The average age of the sample was 29 years old. Table 1 presents a summary of the sample sizes from each region by gender. These groupings were used to explore possible mean differences in vocational interests, values, and abilities as a function of where they live and attend school.

Table 1. — Summary of Normative Data by Region and Gender

Region Males Females Totals
West 5,995 5,157 11,152
South 3,342 3,474 6,816
Northeast 3,537 3,314 6,851
Midwest 3,633 4,186 7,819
Totals 16,507 16,131 32,638

Consistent with previous normative analyses, comparisons were made across gender, grade level, and region to explore which of these factors, if any revealed mean differences of importance. Of these factors, only gender revealed large and consistent mean differences. This suggests that scale means for males and females should be interpreted differently, as has been done in the past. Thus, all four regions were aggregated at the national level and two normative distributions, one for each gender, were determined for educational levels 6 through 12.

Similar analyses were conducted on the COPES Values and CAPS Abilities inventories. As in previous years, separate normative distributions were produced only when mean differences were observed that strongly and significantly influenced the interpretation of scores.

Normative analyses of the CAPS Abilities battery revealed mean differences as a function of grade level. The student profiles reflect this trend, such that grades 8-9 are combined separately from grades 9-12.

The multiple profiles discussed here have been developed using best practices methodology. Our goal throughout this process has been to increase the overall meaningfulness and effectiveness of the recommendations made by those who rely on the COPSystem VIA to assist them as they guide and influence examinees during their career exploration process.

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Learn more about the career clusters measured by the COPSystem.

A Brief Summary of the Reliability and Validity of the COPSystem Assessments

A career guidance assessment program is a valuable way to increase self-awareness and professional competence among students and working adults. The COPSystem consists of the COPS Interest Inventory, the CAPS ability battery, and the COPES work values survey. All three are long established, reliable, and valid assessments relating interests, abilities and values to occupations and occupational information. Reliability and validity information is presented in this article.

Career Occupational Preference System Interest Inventory (COPS)

In terms of reliability for the COPS, alpha coefficients for each scale range from .83 to .91. Numerous studies have been conducted to establish the construct validity of the COPS. Correlations of the COPS interest scales to other similar assessments have been used to establish concurrent validity. In comparing the COPS with the Kuder, correlations between conceptually similar scales ranged from .21 to .49 which were significant and were as high as would be expected. In this study, 89% had at least one of their top three areas of interest the same on both the COPS and the Kuder.

When compared to the Holland based Vocational Preference Inventory (VPI), correlations between conceptually similar scales ranged from .50 to .70. To add further support to the construct validity of the COPS, declared major of entering college freshmen was compared to COPS scores and for 71% of the sample, declared major matched one of the top three measured interests. A long-term predictive validity study showed that 64% of students were in a job or college major that matched one of their three highest interest areas from one to seven years after taking the COPS.

Career Ability Placement Survey (CAPS)

The CAPS test-retest reliability coefficients ranged from .70 to .95. To establish concurrent validity, correlations with the Differential Aptitude Tests (DAT) were obtained and ranged from .65 to .81 between conceptually similar tests. Correlations were obtained between CAPS tests and grades in specific subject areas. These correlations ranged from .30 to .60 between the CAPS tests and the subject to which it was most closely related. For example, the CAPS numerical ability test had the highest correlations with grades in math. These results are significant and demonstrate the validity of the CAPS. Predictive validity studies show that ability scores are significantly related to subsequent career choice.

Career Orientation Placement and Evaluation Survey (COPES)

With regards to the COPES, alpha reliabilities ranged from .60 to .85. Concurrent validity studies demonstrated that the scales on the COPES are correlated .40 to .60 to conceptually similar scales on the DF Opinion Survey and the Allport Vernon which are as high as would be predicted. The COPS scores were compared to the COPES scores to confirm the validity of the values scores as related to the interest clusters. This analysis explored the relationship between interests and work values by selecting a sample of examinees with scores in a single interest area at the 75th percentile or higher and establishing a COPES profile.

The findings demonstrated the relationship between work values and interest scores that is reflected on the COPSystem Comprehensive Career Guide. A preliminary follow-up study for the COPES found an 89% hit rate for work values matched to subsequent career or college major choice. This article is a brief summary of technical information. For a more comprehensive discussion of the reliability and validity of the COPSystem please see the individual Technical and/or Examiner’s Manual for each assessment.

Stability of the COPS Interest Inventory Scores Between Eighth and Twelfth Grades

In an effort to provide longitudinal validity data for the COPSystem assessments, the COPS Interest Inventory was used to determine the stability of students’ interests from the eighth to the twelfth grade. The effectiveness of career exploration classes in high school was also examined.

The subjects in this study were 807 females and 668 males from a metropolitan school district in South Carolina. All graduated between the years of 1997 and 2001. The students were tested in the eighth grade and again in the twelfth grade. Only those students that completed both administrations were included in the study and inventories were matched by comparing names, gender and identification numbers.

Profiles of each student’s three highest areas of interest were plotted for both sets of scores and then compared. Of all the students tested, 87% had at least one interest that remained one of their top three areas of interest between the eighth and twelfth grades. The percentage of students who reported an exact match between the first ranked area of interest in eighth grade and first ranked interest in twelfth grade was 27%.

“87% of the students retained at least one of their top three areas of interest between the eighth and twelfth grades.”

Student’s responses on the Needs Assessment section of the COPS were also collected and analyzed for a subset of the sample.This subset consisted of 254 females and 233 males who graduated between the years of 2000 and 2001. The Needs Assessment Summary is presented in the form of two questions at the end of the COPS inventory. The question that was analyzed for this study consisted of a list of 19 skills which examinees were asked to indicate by either a “yes” or “no” response if they needed additional help in these areas.

The percentage of students in the total sample who answered “yes” to each item was calculated for both the initial and the follow-up administrations and compared. The percentage of “yes” responses on items related to educational/career planning declined from 47% to 23% between the eighth and twelfth grade administrations. These items included reading skills, language skills, math skills, study skills, decision-making skills, interpersonal skills, career planning skills, educational planning skills, how to find college information, applying to a college or university, applying for financial assistance, and finding military service information.

The percentage of “yes” responses on items related to placement and job skills declined from 40% to 19% between the eighth and twelfth grade administrations. These items included how to find job information, how to find a job, how to apply for a job, how to interview for a job, how to keep a job, obtaining entry level job skills, and upgrading of existing job skills.

“Results indicate that high school career guidance classes and programs provide helpful information to students.”

As evidenced by the Needs Assessment Summary, exposure to career guidance and information offered through the school-to-work program was of significant help to students. Providing career assessments, guidance information, and counseling to students gives them valuable information that they may use for college and job placement.

COPS-P, CAPS and COPES Validity

The COPS-P System is a career awareness program consisting of three measures: Professional Interests (COPS-P), abilities (CAPS), and work values (COPES).

The COPS-P, CAPS, and COPES may be used together and summarized on a single profile, the COPS-P Comprehensive Career Guide. The following four tables show validity evidence for each inventory. Interpretation of these measures is organized around a comprehensive set of occupational clusters, which represent all possible jobs. Results are keyed to major sources of occupational information and related activities, skills, college majors, school planning, and training programs.

The COPS-P System structure of occupations is based on a theoretical clustering of occupations having highly similar job activities. Research on statistical confirmation of the theoretical structure upon which the COPS-P System is based dates back to the work of L.L. Thurstone in 1931 and its roots may be traced from that pioneering effort to the work of J. P. Guilford and the classification system presented by Anne Roe.

The theoretical basis of the COPS-P System provides a broader, more comprehensive base for career guidance than those instruments based on a few arbitrarily selected and empirically developed occupational scales. The COPS-P Interest Inventory provides occupational information organized into Career Clusters for the entire world of work, as shown in Table 1.

Table 1. Career Clusterscops-p-validity-table-1

In addition to its strong theoretical base, the COPS-P has substantial validity evidence. The COPS-P has demonstrated factor validity; the items have been factor analyzed and demonstrate the occupational structure presented above. Correlations between scales on similar types of interest inventories further demonstrate the validity of the COPS-P. Table 2 presents correlations between the COPS-P and scales on the SCII. It can be seen that the highest correlations have been found between conceptually similar scales on the two inventories. Complete information may be found in the COPS-P Technical Manual.

Table 2. Correlations between COPS-P and SCII.cops-p-validity-table-2

The CAPS and COPES may be used in conjunction with the COPS-P. Results for the three assessments are combined on the COPS-P Comprehensive Career Guide. The CAPS is a widely used ability battery with well established validity and reliability information. Table 3 shows the correlations of the CAPS to another ability battery, the GATB. Correlations are high as would be expected between the conceptually similar tests and are shown in italics.

Table 3. Relationship of CAPS to GATB.cops-p-validity-table-3

Table 4. Relationship of COPES to MBTI.cops-p-validity-table-4

The COPES is the work values assessment component of the COPSystem battery. It is also widely used and has well established validity. A study was conducted comparing the COPES to the Myers Briggs Type Indicator (MBTI). Although these two assessments are somewhat different in design, both may be used to explore career issues such as the motivation behind selecting and remaining in a particular occupation.

The COPES survey was designed to measure personal values that relate to occupational selection and job satisfaction. Work values measured by the COPES include Investigative, Practical, Independence, Leadership, Orderliness, Recognition, Aesthetic and Social, and are keyed to the COPSystem Career Clusters. The Myers-Briggs was developed as a means of applying Carl Jung’s theory of psychological types to personality assessment. The MBTI classifies individuals as one of 16 possible types, depending on preferences related to functioning in the areas of Introversion vs. Extraversion, Sensing vs. Intuitive, Thinking vs. Feeling, and Judgement vs. Perception. In career counseling, the different personality types are assumed to be the most attracted to and satisfied by particular occupations.

In the study, 299 high school and college students completed both the COPES and the MBTI. MBTI scores were converted to continuous scores as detailed in the MBTI Manual. Pearson correlations were computed between scales on both instruments and are shown in Table 4. As expected, there were significant correlations between like named, theoretically similar COPES and MBTI scales.

The finding of this study supported the hypothesized relationships between the COPES and the MBTI scales. Each of the eight COPES scales were significantly correlated with the expected MBTI scale, reconfirming the validity of the instrument. As demonstrated by the results of this study, the COPES is a useful measure of work values which are known to play an important role in occupational selection and satisfaction.

Further evidence of the validity and reliability for all three assessments may be found in their respective Technical Manuals.

COPS-PIC Norms and Reliabilities

The COPS Picture Inventory of Careers (COPS-PIC) norms are based on 1,930 students in grades 6-12 from across the United States. There are still significant differences found on some of the scales for males and females, justifying separate norms by gender. No significant differences were found by region or grade level so the norms are combined for these groups. Reliabilities, intercorrelations and additional validity data are reported in the COPS-PIC Manual.

Reliabilities for the scales ranged from .84 to .93, with a median of .89. The Manual also includes a more in-depth description of how to use the COPS-PIC scoring keys. The most recent profile sheet has the norms for males and females presented in the same manner as in the past. The four-page Self-Interpretation Profile and Guide includes updated pictures to facilitate occupational exploration.