How to show that 9 > 221: Collect judgments in a between-subjects design.

In between-subjects (BS) designs, different groups may be asked to make judgments on numerical rating scales.According to judgment theory, judgments obtained BS are not an ordinal scale of subjective value.This article illustrates how BS designs can lead to strange conclusions: When different groups judge the subjective size of numbers, 9 is judged significantly larger than 221.The theory is that 9 brings to mind a context of small numbers, among which 9 seems "average" or even "large"; however, 221 invokes a context of 3-digit numbers, among which 221 seems relatively "small."Within-subjects, however, judges would not have said 9 > 221.Implications of this problem and suggestions for dealing with it are discussed.