KTEA™-3 29

STANDARDIZATION AND PSYCHOMETRIC PROPERTIES OF THE KTEA-3

This section of the chapter describes the standardization sample and provides reliability and validity information for the KTEA-3.

Standardization

The KTEA-3 Comprehensive Form was standardized with an age-norm sample of 2,050 examinees ages 4 through 25, and a grade-norm sample of 2,600 students in prekindergarten through grade 12. For each grade level, the sample size ranged from 150 to 200 students (with half of the examinees tested in the Fall and the other half in the Spring). For each age level, most sample sizes ranged from 120 to 160 examinees, except age 4 with a sample size of 100, and ages 19–20 and 21–25, each with a sample of 75.

The KTEA-3 Comprehensive Form contains two parallel forms, so approximately half of the norm sample was administered Form A and the other half was administered Form B. The standardization sample was stratified to closely match the U.S. population. Thus, on the variables of gender, ethnicity, parental education, geographic region, and special education or gifted placement, the standardization sample closely corresponded to data from the 2012 American Community Survey of the U.S. Census Bureau. Self-education111111111 was used instead of parent education for examinees ages 19–25.

Reliability

The internal-consistency reliability of the KTEA-3 Comprehensive is strong for both Forms A and B. The average internal-consistency reliability value across grades and forms for the Academic Skills Battery Composite is .98. The averages for the Reading, Math, and Written Language Composites are .95, .97, and .94, respectively. The average reliability values by grade for the Supplemental Composites range from .72 to .98. Reliability values based on age groups are very similar to what was reported for the reliability values found with the grade-level samples. Table 2.1 presents the internal consistency reliability values of the Comprehensive Form subtests and composites averaged across forms.

Alternate-form reliability values were calculated by administering the two forms of the KTEA-3 Comprehensive to a sample of 306 examinees. The forms were administered 7.5 days apart, on average. Similar to the internal-consistency reliability values, the values for the alternate-form reliability are also high. The Academic Skills Battery Composites showed very high consistency across time and forms (mid-.90s). The Reading, Math, and Written Language Composites have alternate-form reliabilities in the high .80s to mid .90s. These strong values indicate that the alternate forms of the KTEA-3 will be useful for reducing practice e ects when the test is administered more than once. Table 2.2 shows the alternate form reliability values.

30 ESSENTIALS OF KTEA™-3 AND WIAT®-III ASSESSMENT

Table 2.1 Average Split-Half Reliability Coefficients for Subtests and Composites

Note: Adapted from Tables 2.1 and 2.2 of the KTEA-3 Technical & Interpretive Manual

(Kaufman & Kaufman, 2014b). All reliabilities are based on the average of both forms combined. Mean grade-level values and mean age-level values were calculated using Fisher’s z transformation.

KTEA™-3 31

Table 2.2 Alternate Form Reliability Coefficients for Subtests and Composites

Note: Adapted from Table 2.4 of the KTEA-3 Technical & Interpretive Manual (Kaufman & Kaufman, 2014b). The KTEA-3 scores are based on grade norms. All reliability coe cients were corrected for the variability of the standardization sample.

32 ESSENTIALS OF KTEA™-3 AND WIAT®-III ASSESSMENT

Validity

The validity of the KTEA-3 was demonstrated via multiple methods. Intercorrelations between the subtests and composites were calculated to show the relationships between the academic domains. Factor analyses were conducted to show that the structure of the test is empirically grounded. Correlations with other instruments were also conducted to evaluate the construct validity of the test. Finally, special population studies were conducted to show the e cacy of applying the KTEA-3 to the assessment of examinees with learning disabilities, language disorder, mild intellectual disability, attention-deficit/hyperactivity disorder, and academic giftedness. The results of these special studies are detailed in the Clinical Applications chapter in this book.

Confirmatory factor analysis was conducted to investigate the relationships between the KTEA-3 Comprehensive Form subtests and composites in a systematic manner. The factor analysis proceeded in a stepwise fashion with six subtests that compose the Reading, Math, and Written Language Composites, in addition to the three subtests that make up the Oral Language composite, yielding a final model comprised of four factors. The final model had good fit statistics and all subtests had high loadings on their factors. The results of the factor analysis are shown in Figure 2.2.

The KTEA-3 Comprehensive and Brief Forms were administered along with other tests of achievement and cognitive ability to a subset of the standardization sample. In addition to the results of the correlational data already reported with the original KTEA-II (see Rapid Reference 1111111112.3), correlations were calculated between the KTEA-3 Comprehensive and Brief Forms. Further correlations were calculated between the KTEA-3 Comprehensive Form and the following achievement tests: WIAT-III, Woodcock-Johnson III Tests of Achievement (WJ III ACH; Woodcock, McGrew, & Mather, 2001), and the Clinical Evaluation of Language Fundamentals, Fourth Edition (CELF-IV; Semel, Wiig, & Secord, 2003). A summary of the KTEA-3 Comprehensive Form correlational studies with the WIAT-III and WJ III ACH are provided in Table 2.3. The results of the studies with the WIAT-III and WJ III ACH are very similar to those found with the KTEA-II. That is, most correlations between like-named composites were in the midto high-.80s, and correlations between most of the total achievement scores hovered between the high .80s and .95.

The tryout version of the KTEA-3 and the CELF-IV Formulated Sentences subtest were administered to 63 examinees to evaluate the validity of the newly revised KTEA-3 Oral Expression subtest. The CELF-IV Formulated Sentences and the KTEA-3 Oral Expression subtest correlated .64, which supported the validity of the newly revised KTEA-3 subtest.

In addition to the correlational data showing the relationships between the KTEA-3 and other tests of academic achievement, the KTEA-3 Technical & Interpretive Manual provides correlations between the KTEA-3 and two tests of cognitive ability: the KABC-II and the Di erential Abilities Scales, Second Edition (DAS-II; Elliott; 2007). Sample sizes were 99 and 122 for the studies with the KABC-II and DAS-II, respectively. In addition, the WISC-V Technical and Interpretive Manual

(Wechsler, 2014) provides correlations between the WISC-V and the KTEA-3 with a sample size of 207.