Does demographic targeting actually work?
Less well than the industry's reliance on it suggests. Demographic categories are weak predictors of purchasing behaviour, and the evidence for this has been accumulating for years without changing practice much.
Why it persists. Demographics are easy to obtain, easy to describe, and easy to explain in a meeting. "Women aged 25–44, ABC1" is a legible audience definition. Whether it identifies the people who will actually buy is a separate question.
What the evidence shows. Analyses of purchasing data repeatedly find that brands within a category have remarkably similar buyer profiles — competing brands are bought by much the same kinds of people in much the same proportions. If two rival brands have near-identical demographic profiles, demographics cannot explain why someone chooses one.
Studies of digital audience segments have also found substantial inaccuracy in third-party demographic data itself, with a meaningful proportion of age and gender classifications simply wrong — so campaigns are frequently targeting a demographic they are not actually reaching.
What predicts behaviour better:
Past purchase behaviour in the category, which is by a wide margin the strongest signal.
Current intent — what someone is searching for or researching now.
Situation and context — what they are doing, where they are, what moment they are in. A search for "emergency plumber" tells you everything; the searcher's age tells you nothing.
Needs and use cases, which cut across demographics entirely.
Where demographics do matter: products with a genuine biological or legal basis for restriction; media planning where consumption differs sharply by age; and regulatory compliance, since some advertising must not be shown to children.
The commercial cost of getting it wrong. Narrow demographic targeting excludes buyers who do not fit the assumption — and since the profile is usually wrong, that means excluding real customers while paying a premium for the targeting. Several analyses have found broad targeting outperforming narrow demographic targeting once the cost of the targeting itself is accounted for.
The direction of travel is toward contextual and intent signals, accelerated by privacy restrictions on the data demographic targeting depended on.