Discrimination claims are usually built on one of two theories, and the choice determines what the claimant must prove. The distinction between intent and effect runs through most equality law.
Two ways of framing the same complaint
A disparate treatment claim alleges that someone was treated worse because of a protected characteristic. The core question is why the decision was made, which makes motive central to the case.
A disparate impact claim alleges that a rule applied uniformly to everyone falls more heavily on one group. Motive drops out, and the argument shifts to the observed effect of the rule.
The same facts can support either framing. Which theory is pleaded shapes the evidence gathered, the defences available and, frequently, whether the claim survives an early challenge.
Neutral rules with uneven effects
Impact claims typically target selection criteria that appear unrelated to any protected characteristic. Height requirements, credit checks, fixed shift patterns and criminal record screens have all been examined this way.
None of those criteria mentions a group, yet each can exclude one group at a markedly higher rate. The claim is that the criterion functions as a filter regardless of what it was designed to do.
Courts then ask whether the criterion is genuinely necessary for the role or service. A rule that predicts performance well is treated very differently from one adopted out of habit.
The burden moves between the parties
Impact cases usually proceed in stages. The claimant first shows a substantial difference in outcomes, which shifts the argument to the respondent rather than settling the case outright.
The respondent must then justify the practice, commonly by showing it serves a legitimate aim and is a proportionate way of achieving it. Vague assertions of business need rarely carry that burden.
If justification succeeds, the claimant may still show that a less exclusionary alternative would have served the same aim. That final step is where many of these cases are decided.
Why evidence about groups does the work
Because impact claims turn on outcomes, they depend on comparisons between the group affected by a rule and an appropriate pool. Defining that pool is often the most contested part.
Choosing the wrong comparison group can make a real difference vanish or invent one that is not there. Both sides usually put forward different pools and argue about which is the honest one.
This evidentiary demand also explains why impact claims are more common against large institutions. Small employers may produce too few decisions for any pattern to be distinguished from ordinary variation.
The doctrine is not uniform or fixed
Not every system recognises effects-based liability, and those that do apply it to different fields. Some extend it across employment, housing and lending, while others confine it much more narrowly.
The terminology also diverges. Similar reasoning appears as indirect discrimination in some jurisdictions and adverse effect discrimination in others, with meaningful differences in the justification standard.
These rules are revised by legislatures and reinterpreted by courts, so the position in any particular place at any particular time has to be checked rather than assumed.