Nationally normed standardized tests are not the same as content tests. Most are familiar with tests designed to determine if a child has learned material recently taught. These are the common content tests that are scored by the number the child gets right, thus knowing if he/she learned the “content” taught. But a nationally-normed standardized test is quite different. This type of achievement test takes many years to publish because a norm group and norm scores must be established. The questions are designed to reflect a general course of study rather than any scope and sequence of a particular state or curriculum. A nationwide norm group representing differing groups (minorities, urban and rural students, differing academic abilities, differing socio-economic circumstances, etc.) and different grade levels take the test by a defined standardized method. This group is designed by strict standards so that the scores are not skewed by environment and therefore the resulting norm scores will be a fair comparison for all subsequent students taking the test. The scores by this extensive norm group then become the basis of the percentile rankings. The score that is right in the middle of the group, 50% scoring higher and 50% scoring lower, becomes the 50th percentile score. This score is not related directly to how many answers were correct, but rather to how many students scored higher and lower. All other percentile rankings are generated similarly such that a percentile ranking of 40 means that 40% of the students scored lower and 60% higher, etc. After the achievement test with norm references is published and released, each subsequent student taking the test is compared with the norm group score to derive a percentile ranking. For any given subtest or subject, a 50 percentile rank by a student means that he or she scored in the middle of the “bell curve” or right where half the students scored lower and half higher: an average score. By definition though, an “average” score actually ranges from the 23rd to the 76th percentiles. Likewise, a higher-than-average percentile of 84 means that the student scored higher than 84% of other students and lower than 16%. Any percentile score above 50 puts the student in the top half of nationwide scores. Half of all children, by definition, should score below the 50th.Respected versions of nationally normed standardized tests include the Stanford, the Iowa, and the California. It is extremely important that these tests be administered according to the strict standardized parameters set forth by their publishers. The entire scoring is predicated on the fact that all students take the test exactly the same way. In fact, some of the publishers and some educators have criticized the homeschooling community, suggesting that we do not adhere to the standardized instructions. BJUP with HSLDA have argued on our behalf so that these tests remain available to us and do not require administration by a certified teacher, who is more trusted by the publisher to maintain the integrity of the test. CHEWV will continue to require their administrators to follow the standardized procedure that we agree to as a matter of honesty and integrity. Without strict standardization in administration, the scores are compromised, our excellent statistics are suspect, and our ability to use these nationally recognized tests is at risk. CHEWV is pleased that our volunteers hold to a high Christian standard.
Understanding Percentiles and
Nationally-Normed Standardized Tests
