Small changes near a concept’s midpoint carry more meaning than changes at the extremes.

Evidence

Two other key choices are the inflection points at the top and bottom of the S-curve. These are critical points where the changes in X toward 0.0 or toward 1.0 have little semantic meaning. These might be called the points of “relatively flat semantic returns” in analogy with the log. Conversely, in the middle zone, small changes in X have large meaning changes. This makes the choice of 0.50 critical, because it in part determines this zone of “steep semantic returns.” — Gary Goertz, Social Science Concepts and Measurement, 654

Categorization

• DEFINE: Introduces ‘flat’ versus ‘steep semantic returns’ — the metaphor borrowed from the log function that explains why the crossover point matters most.