The ratio of mental age to chronological age multiplied by 100 is known as what?

• A. Ratio IQ Score
• B. Standard IQ Score
• C. Deviation IQ Score
• D. Growth Index

Answer: (A)

This item is about the original way intelligence was quantified by comparing how a person’s mental development stacks up against their actual age. When you take mental age and divide it by chronological age, then multiply by 100, you get the Ratio IQ Score. This makes sense because a person whose mental abilities match their age clocks an IQ of 100; if their mental age is higher, the IQ rises above 100, and if it’s lower, the IQ falls below 100.

Historically, this ratio-based method stood alongside other ways of expressing intelligence. A Standard IQ Score and a Deviation IQ Score describe scores that are normed and scaled against age groups using a spread (mean of 100 with a standard deviation, typically 15), rather than a simple MA/CA ratio. Growth Index isn’t a standard term used for IQ.