Using letter grades to classify student performance on an exam is an example of measurement on which scale of measurement?

Using letter grades to classify student performance on an exam is an example of measurement on which scale of measurement?

• A. Nominal
• B. Ordinal
• C. Interval
• D. Ratio

Answer: (B)

Letter grades give you an ordered ranking of performance: A is better than B, B better than C, and so on. The crucial point is that this ordering exists, but the size of the steps between grades isn’t defined or guaranteed to be equal. You can say someone did better overall, but you can’t assume that the difference in achievement between A and B is the same as between B and C. That ability to rank without equal intervals is what makes it an ordinal scale. In contrast, nominal scales have no inherent order, interval scales require equal spacing between values, and ratio scales add a true zero point and meaningful ratios. So using letter grades to classify exam performance exemplifies ordinal measurement.

Letter grades give you an ordered ranking of performance: A is better than B, B better than C, and so on. The crucial point is that this ordering exists, but the size of the steps between grades isn’t defined or guaranteed to be equal. You can say someone did better overall, but you can’t assume that the difference in achievement between A and B is the same as between B and C. That ability to rank without equal intervals is what makes it an ordinal scale. In contrast, nominal scales have no inherent order, interval scales require equal spacing between values, and ratio scales add a true zero point and meaningful ratios. So using letter grades to classify exam performance exemplifies ordinal measurement.