Most standardized tests are initially scored with raw scores. Such scores must later be converted to other types of ratings for comparative or interpretive reasons. Raw scores are simply the number questions or problems the student answered or solved correctly. Without knowing how many questions were on the test or the point value of each question, raw scores are impossible to decipher in terms of percentile, grade, or measured progress.
Raw Scores Lack Interpretive Meaning
To illustrate what raw scores are and why such results have little initial meaning, consider an average fifth-grade student taking a standardized test. Upon completion of the text and subsequent marking, the student receives a raw score of 52. Without more information, the raw score has no meaning. If the test consisted of 55 questions, a raw score of 52 would be a superior score. Alternatively, if the test had 112 questions, a raw score of 52 would be a below-average score.
The Need to Convert
For a raw score to have meaning, it must be converted into another type of score to allow uniform comparison to other students taking the identical test, to measure of progress or for other reasons. Percent correct, percentile rank, developmental standard and grade equivalent are all examples of scores derived from raw scores. Each type of score requires a different computation and represents a different measurement. Grade equivalent, for example, converts raw scores into a decimal number indicative of the academic grade year and month for which such scores show proficiency. A grade equivalent score of 5.6, for example, indicates proficiency at the level of fifth grade, sixth month of the school year.
Raw Score to Percentile Rank
Most standardized test score reports include both a raw score and an already-converted percentile rank. Percentile ranks based on raw scores indicate where a student falls in comparison with other students of the same age or academic level, taking the same test. For example, a percentile rank of 64 means a student's raw scores were better than 64 percent of other students taking the same test at the same time and developmental ability. Computing percentile scores from raw scores can follow any number of formulas, depending on whether scoring is converted based on the sample or based on the normal curve.
The Necessity of Raw Scores
If raw scores have no meaning, it is logical to wonder the purpose of such scores. In most instances, raw scores allow for computerized grading of large batches of tests. In simplest terms, the use of raw scores is much like finding an unknown variable in an algebraic equation. In algebra, finding the value of an unknown variable produces the final answer to a mathematical question. By identifying an previously unknown raw score, the final answer of how a student performed is achieved.