Discrepancies in Test ScoresBy Inderbir Kaur Sandhu, Ph.D
Q: My daughter was tested at the end of 1st grade for a gifted program. She scored in the 99 percentile on the Naglieri but her scores on the Iowa Test of Basic Skills were in the 40's. All tests were administered one grade level above. Can you help me understand why there is such a discrepancy between the two scores? She just finished 2nd grade in a normal classroom. She did well and her teacher again thought she was very bright. She had independent spelling lists and read in the high reading group but did not even score high enough to be placed in a high ability cluster group within her school.
Where do I go from here?
A: The Iowa Test of Basic Skills (IBTS) is a nationally standardized test used across the US. Test-takers are administered in the same way across a specified reference population (e.g., age groups, grade groups, etc.). Hence, the score interpretations are based on a comparison of the test taker's performance to the performance of other students in the nation, in short, measuring students against their peers. As the test name indicates, it measures basic skills such as vocabulary, word analysis, reading comprehension and listening. On the other hand, the The Naglieri Nonverbal Ability Test (NNAT) measures ability without the requirement of reading, writing, or speaking. The focus is on reasoning and problem-solving skills which is considered ideal for those with limited English proficiency.
The IBTS is a grade based achievement test while the NNAT is an IQ test. This may clearly cause some differences in the scores. It has been researched that gifted children are best identified by reasoning tasks (such as verbal, spatial, mathematical), and many score lower in processing skills, such as visual-motor speed (as they may be reflective and perfectionist) or short-term auditory memory (since their memory for meaningful material may be much better than for non-meaningful). These are usually the basics of IQ tests. In contrast, achievement tests determine how advanced a child is in academic subject areas such as reading, math, writing, and spelling.
In your daughter's case, there appears to be some concerns as she has high reading abilities. The full detailed break down of the score is needed to interpret her scores and determine weak areas that may have caused a drop in scores. Perhaps, it would be a good idea to see someone from the school for further advice on the scores. The most important issue here is to identify her weak areas based on her grade level and seek advice on what can be done to improve those areas on concern. Best of luck.
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