MMT grades and levels of assistance are examples of which scale?

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

Answer: (A)

The idea being tested is how to classify clinical measurement scales by order and spacing. MMT grades and levels of assistance form an ordinal scale: the categories are arranged in a meaningful order (greater strength or more needed help), but the distance between adjacent categories isn’t guaranteed to be equal. For example, the jump from slight strength to moderate strength isn’t guaranteed to be the same increment as from moderate to strong, and you can’t perform arithmetic that assumes equal steps or a true zero-based ratio.

That’s why these are not nominal (which would be just categories with no inherent order), not interval (which would require equal distances between categories without implying a true zero), and not ratio (which requires both equal intervals and a meaningful true zero for meaningful ratios).