Research shows people often don't understand the intended meaning of a scale. For instance, on a 100-point employee scale, anything above 75 should be "respectable," but managers often feel pressured to inflate scores to near 100.

We use average ratings as a primary mental shortcut. If a score is high enough, many users won't even bother looking at the specific details of a place.

Humans have a deep-seated compulsion to review and categorize. A five-star or ten-point scale provides a "texture" to our gut feelings, allowing us to transpose subjective emotions into a structured format.