The midpoint of a scale is rarely the real crossover for a concept

Evidence

The natural thing would be to use level 3 as the 0.50 crossover point because it is the middle of 1–5. It is again important to look at the meaning of that level in the coding rules, as well as specific cases that get that particular coding. If one does so, it seems pretty clear that 0.50 is too low for the concept of repressive government. Level 3 is defined as “extensive political imprisonment” and “execution or other political murders and brutality may be common.” So I have put level 3 at 0.65. — Gary Goertz, Social Science Concepts and Measurement, 794

Categorization

• QUESTION: Goertz’s 0.65 placement is asserted as ‘pretty clear’ — is there a principled rule, or is it irreducibly interpretive?