Adia J. Garrett, Ph.D. (August 2008)
(Mentor: Linda Baker)
Before test scores should be used for educational decision-making, it is important to determine if a test actually measures the skills that test developers claim it measures and to determine if the test presents difficulty that is unrelated to the skills being measured. This study explored the role that children’s ability to interpret pictures plays in their performance on the Word Knowledge subtest of the Gates MacGinitie Reading Test (GMRT). Research on children’s picture perception has demonstrated that interpreting meaning from pictures is a subjective process and related to the viewers ‘age, familiarity with the concepts pictured, and ability to interpret pictorial cues. Studies have also demonstrated that African American children scored significantly lower than their European American peers on a receptive picture vocabulary test. However, these studies did not directly measure the role that picture interpretation skills played in test performance.
To address the limitations of previous picture vocabulary research, 128 second grade students from two predominantly African American school districts were randomly assigned to the following test conditions: a). Standard Format. The researcher administered the Word Knowledge subtest using the standardized directions. For each picture, the children’s task was to select one word from a list of four that best matched the picture. b) Think-Aloud. In addition to the standard instructions, students discussed their thoughts as they selected their responses. c) No Picture. For each vocabulary word, pictures were replaced with definitions that were both written and read to the students. d) Free-Response. Students were asked to tell the researcher what the picture showed; no response choices were provided.
These test conditions were designed to address three questions: a) Did performance differ as a function of test condition? b) What role did the part of speech of the vocabulary item play on children’s performance? c) What processes did children use to select their answers, especially for frequently missed items? Results revealed that thinking aloud did not hinder or facilitate performance. Overall there were no differences in performance based on type of stimulus (pictorial or definition); however, item-level analyses revealed 6 items in which performance differed based on stimulus type. For children in the standard and think-aloud conditions, performance was better on nouns and verbs than on adjectives, and performance on nouns and verbs was comparable. For the no picture condition, performance was best on verbs and performance on nouns and adjectives was comparable. Think-alouds and free-responses revealed possible explanations for why students frequently missed some items, such as misinterpreting key elements of the picture, choosing distracters, and using one’s imagination to justify incorrect answers.
The pattern of errors that students made on the test provided information regarding how teachers can prepare children for success on picture vocabulary tests. For example, they can teach children how to consider several possible answers before making a final choice and how to check their answers for accuracy. Teachers can also instruct children how to interpret the conventional pictorial cues that are used in line drawings. Children’s patterns of responses also revealed how test administration could be modified in a way that may minimize errors. These modifications include telling children that the words could represent multiple parts of speech (noun, verb, or adjective) and providing both pictures and verbal definitions to minimize errors related to picture perception. In addition, line drawings could be substituted for more authentic color pictures or photographs. Future studies are needed to determine if the patterns of responses would be replicated in a larger, more diverse sample of children.