The Wechsler Individual Achievement Test (WIAT) is a test of achievement for children and adolescents that is given by psychologists or other qualified professionals and is linked to the WIAT, a test of intelligence. The WIAT includes scores for Reading, Mathematics, Oral Language, and Written Language, as well as a Composite score. The average score for all tests and subtests is 100; thus, a score of over 100 is above average and below 100 is below average. The standard deviation for IQ results is 15, which means that about 68% of scores fall between 85 and 115. The test results also provide the raw and scaled score for each test, as well as a percentile rank.
Composite and Subtest Scores
Each area of testing, Reading, Mathematics, Oral Language, and Written Language, is scored individually. The Composite Score is simply an average of these four areas and gives a general idea of the person's school readiness. Each subtest is further broken down into the individual test, such as Word Reading or Spelling, and scores are given for these sub-areas as well.
The first step in analyzing scores is to look at the main WIAT scores. The average score for each test is 100, and the examinee's standard score is labeled STD. Anything from 90 to 109 is considered Average, although 100 is exactly in the middle. Scores from 110 to 119 are considered High Average, from 120 to 129 are Superior, and from 130 and up are Very Superior. On the other end of the spectrum, from 80 to 89 is considered Low Average, 70 to 79 is Borderline, and 69 and below are Extremely Low.
The 95% Confidence Interval is a statistical way of saying the results sometimes might not be accurate. This statistic says that when taking the test, 95% of the time the results will be in the spectrum given. Five percent of the time the results might be outside of the given interval. In other words, the score is about 95% accurate, which is very good for an achievement test like the WIAT.
The next column is usually the Percentile Ranking (PR). The highest possible score here is 99.9%. The average percentile is 50%, so a percentile of 50 would equate to an IQ of 100. This score will show how the examinee did on the test compared to other people his age. If the percentile is 60, for example, he did better than 60% of others who were tested using the WIAT.
For the subtests, the test results will list the Age Equivalent and Grade Equivalent. Ages are listed year:month, so an Age Equivalence of 13:6 means the person being tested is about where a 13 -year-old should be. The Age Equivalency should be compared to the person's actual age to see if they are about where they should be. Anything over 19:11 is considered to be an adult age equivalency.
The Grade Equivalent is recorded as grade:month in the grade. Therefore, a person with a Grade Equivalent of 8:3 is at the stage of an 8th grader in the third month of 8th grade. The highest grade equivalency for 8th grade would thus be 8:9, since there are only nine months of school. Anything over 12:9 is considered to be on college level.
Strengths and Weaknesses
Once the scores are interpreted, the next step is to check for strengths and weaknesses. First, any score below an IQ of 100 should be examined. These areas are weaknesses compared to others of the examinee's age. Next, check for scores that are lower than the other scores. This indicates a personal weakness, even if the score is still in the Average range. Also check for scores that are higher than the others, as this indicates a personal strength. Once strengths and weaknesses are established, they can be worked on or played to.
The WIAT is a great starting point to understand a person's difficulties and successes in school. It can help with learning disability diagnosis, special education placement, and other educational goals.