Percentiles

Percentiles Percentiles are sometimes called percentile ranks. It’s the most common interpretive schemes used to explain standardized achievement tests. It represents how a student’s scores on the test is compared to scores of other students in a norm group. Norm group is individuals who have already taken the test. Percentile scores range from 1 to 99. So, a percentile is used to as a comparison score. It does not show exactly how items the student answered correctly it only shows if the student did good or bad comparing with other students. For example, suppose 50 students took an exam of 25 questions if one of them answered 20 questions correctly, then he got 80 percent of the items correct. But because we do not know what the other students did we cannot identify his
percentile. So, let’s say that the other students got 70 percent of the questions right. Then, the student who got 80 percent of the questions correct did better than all of them and his percentile would be 99. In short the advantage of Percentile is obvious to singular student because it relates his performance over a larger group of students. If all the students did bad and he got a low score but higher than them he will get the higher percentile. However, its disadvantage is that it does not give averages for groups of test-takers, such as a school or a class.
Grade Equivalent scores ( GE) Describes test results based on grade level and months of the school year.
GE will look like this 5.3, 6.1 or 4.5. When you see 4.5 this means grade 4 after the 5th month of the school year. If a student in the fourth grade scores 5.1 after the first month of the school year this means that his scores are similar to grade 5 when they tested after the first month of the year. This does not mean the student is ready to grade 5 because he was not tested on grade 5 materials. He was tested on grade 4 material and did better than the average of grade 5.
The advantage of GE scores is that it gives teachers an opportunity to identify student grade. level skills. However the disadvantage lies on that most parents misunderstand the results and assume that their children might deserve to be upgraded to the next grade according to their interpreted results.
Scale Scores Scale scores are used to identify group test performances at the school or the state. It is also used to compare among class performances or school districts. A scale is the number that represents the student performance on a test. If a student gets high number this reflects his higher
ability.