Consumer behavior research: how to see what people do, not only what they say

Consumer behavior research tries to explain why people buy, use and stop using products. The hard part is that what people say about their choices often differs from what they do. The practical answer is to start with evidence of behavior, such as purchase records, tests and diaries, then use conversations to explain what you see. Survey answers about future intentions are the weakest evidence of the lot.

If you want a step-by-step guide to interviewing shoppers about a recent purchase, see our consumer research guide. This page is about choosing methods that capture behavior and combining them.

A worked example: the vegetarian meals nobody orders

Suppose you run a meal-kit company. In a customer survey, many subscribers say they want more vegetarian recipes, so you add several. Three months later, those recipes are picked far less often than the survey suggested. This example is hypothetical and used throughout the page.

Nobody lied. People may like the idea of eating less meat, forget how they actually choose on a busy Sunday, or pick the answer that sounds reasonable. The survey measured an attitude. Your order data measured behavior. Consumer behavior research is about explaining the gap.

Why stated preferences mislead

Jakob Nielsen of Nielsen Norman Group summarizes the rule for product research: watch what people actually do, do not believe what they say they do, and definitely do not believe what they predict they will do. He gives three reasons self-reports drift from the truth: people bend answers toward what they think you want to hear or what is socially acceptable; they report what they remember, and memory is unreliable; and they rationalize what they did. NN/g

That does not make attitudes useless. NN/g describes attitudinal research (asking about thoughts and feelings) and behavioral research (observing actions) as complementary, and says the mismatches between the two are often a good source of insight. NN/g on attitudinal and behavioral research

Methods that capture behavior

NN/g lists analytics and A/B testing as behavioral methods; an A/B test compares two versions to see which performs better on a behavioral measure such as conversion. NN/g

Diary studies are especially useful for purchase decisions that unfold over time. Participants report experiences as they happen, over a period from a few days to a month or longer, and the method is done remotely, often at lower cost than field visits. NN/g suggests roughly 5 to 12 participants for a small discovery project, and a broad guideline of about $40 per hour of expected time for a general U.S. sample. NN/g diary studies For the meal-kit example, a two-week diary where subscribers log each time they choose meals, and why, would show what actually drives the pick.

For context on spending in general, the U.S. Bureau of Labor Statistics' Consumer Expenditure Surveys publish data on consumers' spending, income and demographics, collected through an interview survey for major or recurring purchases and a diary survey for small, frequent ones. BLS

Use interviews to explain the behavior

Once you know what people did, interviews tell you why. Anchor every conversation in a real event: "Open your last order. Walk me through how you picked these three meals." Asking people to look at their own order history reduces the memory problem. Avoid "Would you buy more vegetarian meals?" because it invites a prediction.

In the example, interviews might show that subscribers choose meals in under a minute on their phone and default to dishes they can picture. The fix could be better photos or familiar names, not more recipes. Our guide to interviews versus surveys covers when each method fits, and checking interviews against product data shows how to compare the two.

Talk to people who watch many customers

Some professionals observe consumer behavior every day across thousands of customers: store and category managers, merchandisers, retail analysts and customer support leads. They cannot replace your own customers, but they can tell you which patterns are common in the category and which are specific to you.

Instant Expert can help you reach them. You describe the experience you need, review the people it finds, and it sends your invitations; you pay for the calls that get booked. Directory pages such as data and analytics professionals in grocery retail, marketing professionals in retail and marketing professionals in beauty and personal care show the kind of profiles you might shortlist.

A simple plan

1. Write the behavior you want to explain, such as "subscribers skip vegetarian meals."
2. Pull the behavior data you already have before asking anyone anything.
3. Add a behavioral method where the data is thin: a test, a diary or an observation.
4. Interview a handful of customers about specific recent choices.
5. Where what people say and what they do disagree, treat the behavior as the fact and the explanation as the thing to investigate.

If you want an outside view from people who see many shoppers, start a search with a one-sentence description of the experience you need.