ABSTRACT
One common error is incorrectly determining the student’s chronological age. Since it is “best practice” to determine scores based on the student’s chronological age, rather than grade level, it is critical to determine that correctly. A second common area for those scoring “by hand” is using the wrong table. It is quite easy to read a raw score off the wrong table or from an incorrect line on the appropriate table. Test score theory is based on the notion that, given a large enough population that takes the test, people’s scores will arrange themselves along a normal curve. Determining a score is based on two important items: the student’s age and raw score. Scores that are reported in terms of standard deviations are known as Z-scores. A Z-score indicates how far the score is from the mean in standard deviations.
