Case Study Consulting Psychologist

As a consulting psychologist for a new school system, I have been asked to help with choosing a battery of test to assess the aptitudes, learning abilities and academic levels of individual students. Because of the concerns surrounding the utility (purpose) of the test among young children. I have conducted researched on three test batteries that I founded to be useful or of practical value for my intended purpose. The tests I have chosen are standardized tests and are based off their utility, reliability and validity. So, after carefully researching three articles for the psychometrics of the test to determine its (validity) the ability of the test to measure what it was designed to measure and (reliability) the measurement of consistency. The first test that I have chosen is the Wechsler abbreviate Scale of Intelligence-Second Edition. The test purpose is designed as short and reliable measure of intelligence used primarily in the clinical, psychoeducational and research setting (WASI-II, Wechsler, 2011).  An intelligence test just like an aptitude test, assess the test taker’s ability to cope with the environment, but at a boarder level. This test is often used to screen individuals for a specific program such as gifted, honors or mentally challenged. I chose the WASI-II after reviewing the validity and reliability of the Wechsler Abbreviated Scale of Intelligence, Second. The test showed updated norms; the standardization of the WASI-II was conducted from 2010 to May of 2011 on a sample of 2,300 individuals age 6-90, divided into 23 age groups, each group had 100 participants.  The group studied: ADHD, gifted and talented, intellectual disable (mild-moderate), specific learning disability such as reading, writing, and those with traumatic brain injury.  The article reports the coefficients for the subtest composite reflecting moderate to high above for all age groups which shows internal consistency. The test re-test reliability in children, indicates adequate score stability over a 12-88 day intervening period. The inter-scorer reliability data were high which indicates a clear and well articulate scoring procedure and guidelines. (Wechsler, 2011). The use of this test I find to be sufficient as an estimate of intellectual abilities.

Next ,I found the use of the Wechsler Individual Achievement test Second Edition (WIAT-II) to be a sufficient as its was developed concurrently with the Intelligence Scale for children ( WISC-II: Wechsler,1991) The test primary purpose is designed as a brief achievement test that measures broad skills in reading, spelling, and math computation.  

The norms for the WIAT-II was standard on 5586 individuals with two standardization sample drawn from the population of those k-12 and adults 18-50. Both samples were stratified on the bases of grade, age, sex, race and ethnicity, geographical region and parent(s) educational level. The test take approximately 45 minutes to administer this test.  According to the article the areas covered by the test remains the same, but the depth and range of subject matter has been increased with some new items, and updates of content to reflect changes in curriculum standards and incorporate cutting-edge research acquisition and assessment of educational skills specifically, the listening comprehension or oral expression subset have been modified to coincide with skills demanded of the student in the classroom. The test can identify individual strengths and weaknesses, assist professionals who are determining whether a student is eligible for special education services or has a learning disabilities.  This test can be used as an aid in the educational placement of students, and help with creating instructional objectives or interventions.

The internal consistency reliability estimate of the WIAT-II subtest are generally high with the.  The reliability subtest were only somehow lower end at .70.  The internal consistency reliability of the composite score was very high in both samples. The test and re-test correlation for the subtest across intervals of approximately 10days were consistently moderate and the test- retest were high for composite score which indicate adequate score stability.  According to the article the corresponding subset of the WIAT and WAIT-II are strongly correlated above .80 in school age sample for those subtest with minimal contents changes.  The final test chosen is important because it a good measure of many aspects of academic achievements with a wide variety of relatively brief test. The Woodcock Johnson III.  The WJ-III is based on current theory and research on the structure of human cognitive ability. The theoretical foundation of WJ-III is derived from the Cattell-Horn- Cornell theory of cognitive abilities (CHC Theory) which are two major empirically derived sources of research on the structure of human cognitive abilities informed the development of the WJ –III and has been shown to have a strong correlation with WISC-II.  All of the instruments chosen are cognitive assessment instruments designed to be used with young children. Because all the test chosen are co-normed, the discrepency score do not contain errors from unknown differences that exist when using different test based on different norming groups.