Cognitive complexity is a concept in software engineering that measures how difficult a piece of code is for a human to understand. It goes beyond traditional metrics like cyclomatic complexity by focusing specifically on readability and mental effort, not just the number of possible execution paths.
What it actually measures
Cognitive complexity looks at how much mental effort is required to follow code. It increases when code:
- Has nested structures (loops inside conditionals, etc.)
- Uses complex control flow (if/else chains, switches)
- Requires keeping multiple conditions in mind at once
It tries to answer:
“How hard is this code to read and reason about?”
Shervan K Shahhian
LIBERTY PSYCHOLOGICAL ASSOCIATION 