If you are working through a WAIS-5 report, whether it is your own or a family member’s, the Processing Speed Index is one of the most misread scores, because a lower number here says less about ability than people assume. This guide explains what it measures, how to read the number, and what it does and does not tell you, in plain language.
The Quick Answer
The Processing Speed Index, usually shortened to PSI on a report, is a measure of how quickly and accurately a person handles simple visual tasks: scanning, deciding, and putting pen to paper without needing to stop and reason. It is one of five main index scores on the WAIS-5. On its own it describes one slice of thinking, not a person’s overall ability, and no single index decides what a report means.
What’s Inside the Full Guide
- What Processing Speed actually measures, and the two subtests behind it
- How to read the score, with both the official WAIS-5 labels and a plain-language range table
- How processing speed shows up in everyday life, study, and work
- What a strong score and a lower score can each point to
- Practical, judgment-free next steps, including how to prepare for a school, college, or workplace conversation