A Score by any other name
- In Blog
Understanding the results of a formal evaluation can be confusing. Below is a simple explanation of the terms you may see, and how they are different from the scores of a typical classroom test.
What is a Standard Score?
In the classroom, when you receive a test score in which you got 8 out of 10 questions correct (Raw Score), you are most likely familiar with the concept that you achieved an 80% on your test (Percentage). However, an 80% in geography has no relation to the 77% that you received in chemistry, and neither does it have any meaning in comparison to the other students in these classes.
In order to have a scores that can be compared across different tests, a Raw Score is converted in to a Standard Score. The most commonly achieved raw score is redefined as a Standard Score of 100, and when enough individual people are evaluated you see a Bell Curve (as shown above) emerge. Typically, the majority of people fall between 15 points above or below the 100 mark (called the Average Range). A second increment of 15 points above or below that is described as Above Average and Below Average. Only 2% of a test group will fall within the extreme left or right increments, described as Significantly Above Average and Significantly Below Average.
What is a Percentile Rank?
This is another method of comparison within a group. It describes how the score fares as compared to all the scores measured. If for example a test score falls at the 25th percentile, this indicates that the test taker scored higher than 25 percent of all the other test takers. It would fall within the lower half of the average range. Although it sounds similar, a percentile rank of 25 is not the same as getting 25% on a test (which reflects a raw score).