Where bias comes from
A language model learns patterns from huge amounts of text (see module 2) - and in the process picks up whatever biases are embedded in that data. If the training data disproportionately reflects certain perspectives or historical inequalities, the system mirrors them in its answers, without anyone intending that.
Where bias really matters
Not every bias is equally risky. In a text summary, a slight stylistic bias is usually harmless. In hiring, credit decisions, or medical assessments (see module 20, high-risk areas), the same effect can genuinely disadvantage people - which is exactly why it's specifically regulated under the AI Act.
How to actually check for bias
Break results down by group
Don't just look at the overall success rate (see module 19, evals) - check whether it differs noticeably between relevant groups.
Test with deliberately diverse cases
Deliberately choose test examples that cover different backgrounds, phrasings, and situations - not just the most obvious standard case.
Repeat regularly, not just once
A system that tests fair today may not stay that way after an update or with new data - bias checking belongs to ongoing operations, not just the project start.
Why this matters for you as a decision-maker
"Our AI is neutral" is a claim, not an automatic property. If you use AI in areas that touch people directly, ask specifically: was it tested broken down by group, and how often is that repeated?