Читать книгу Introduction to Abnormal Child and Adolescent Psychology - Robert Weis - Страница 167

Most tests used in clinical settings follow some sort of standardization—that is, they are administered, scored, and interpreted in the same way to all examinees. For example, all 7-year-old children who take the WISC–V are administered the same test items. Items are presented in the same way to all children according to specific rules described in the test manual. These rules include where participants must sit, how instructions must be presented, how much time is allowed, and what sort of help (if any) examiners can provide. Children’s answers are scored in the same way, using specific guidelines presented in the manual (Wechsler et al., 2014).

Standardized test administration and scoring allows clinicians to compare one child’s test scores with the performance of his or her peers. Two children who obtain the same number of correct test items on an intelligence test are believed to have comparable levels of cognitive functioning only if they were administered the test in a standardized fashion. If one child was given extra time, additional help, or greater encouragement by the examiner, comparisons would be inappropriate.

Most standardized tests, like the WISC–V, are norm-referenced. Norm-referenced tests allow clinicians to quantify the degree to which a specific child is similar to other youths of the same age, grade, and/or gender. These tests are called norm-referenced because the child is compared to a normative sample of children, a large group of youths whose demographics reflect a larger population, such as all children in the United States or children with ADHD. Examples of norm-referenced tests include intelligence tests, personality tests, and behavior rating scales (Achenbach, 2015).

Children’s scores on norm-referenced tests are compared to the performance of other children, in order to make these scores more meaningful. Imagine that a 9-year-old girl correctly answers 45 questions on the WISC–V. A clinician would record her “raw score” as 45. However, a raw score of 45 does not allow the clinician to determine whether the girl is intellectually gifted, average, or delayed. To interpret her raw score, the clinician needs to compare her raw score to children in the normative sample, that is, other children who have already completed the WISC–V. If the mean raw score for 9-year-olds in the normative sample was 45 and the girl’s raw score was 45, the clinician might conclude that the girl’s cognitive functioning is within the average range. However, if the mean raw score for 9-year-old children was 30 and the girl’s raw score was 45, the clinician might conclude that the girl has above-average cognitive functioning.

The results of norm-referenced testing, therefore, depend greatly on the comparison of the individual child with the normative sample. At a minimum, comparisons are made based on children’s age. For example, on measures of intelligence, 9-year-old children must be compared to other 9-year-old children, not to 6-year-old children or to 12-year-old children. On other psychological tests, especially tests of behavior and social–emotional functioning, comparisons are made based on age and gender. For example, boys tend to show more symptoms of hyperactivity than do girls. Consequently, when a clinician obtains parents’ ratings of hyperactivity for a 9-year-old boy, he compares these ratings to the ratings for other 9-year-old boys in the normative sample (Achenbach, 2015).

Usually, clinicians want to quantify the degree to which children score above or below the mean for the normative sample. To quantify children’s deviation from the mean, clinicians transform the child’s raw test score to a standard score. A standard score is simply a raw score that has been changed to a different scale with a designated mean and standard deviation. For example, intelligence tests have a mean of 100 and a standard deviation of 15. A child with a FSIQ of 100 would fall squarely within the average range compared to other children his age, whereas a child with a FSIQ of 115 would be considered above average.