Consumer research: how to run interviews that explain buying decisions

Consumer research is the work of finding out how everyday buyers choose, use and stop using products. The most useful place to start is usually a small round of one-to-one interviews about a recent purchase. Recruit people who made that purchase lately, ask them to walk through what happened, and look for patterns across the conversations. Use surveys or sales data afterwards to check how common those patterns are.

This page covers interview-led consumer research: who to talk to, how to find them, what to ask and what to do with the answers.

A worked example: a dog food topper

Suppose you are developing a dog food topper, something owners add to their dog's regular food. You want to know how owners decide to change what their dog eats and what makes them try a new product. This is a hypothetical example.

The research question is specific: "What leads a dog owner to add or switch a food product, and where do they look before buying?" A vague goal like "understand pet owners" would produce interesting conversations and no decision.

Decide who to talk to

Define people by a recent behavior, not only by demographics. "Dog owners who added or switched a food product in the last three months" is more useful than "dog owners aged 25 to 45", because every person in the first group has a recent story to tell.

The GOV.UK service manual suggests recruitment criteria built around a particular experience, and recommends including a spread of people by age, gender, ethnicity, disability and social and economic status. It suggests 4 to 8 participants for a typical round of interviews.

Include people who considered a change and decided against it. They explain what stops a purchase, which is often more useful than hearing why someone said yes.

Find participants

GOV.UK lists several ways to recruit: a research recruitment agency, a professional body or community group, your existing customers (with their permission), and people at a relevant venue. It notes agencies are generally best for recruiting members of the public.

For the dog food example, you could post in a local dog owners' group with the organizer's permission, ask a pet store if you can recruit customers on site, or use a recruitment agency or panel if you need a wider mix. Use a short screener to confirm people match your criteria; see research screener questions.

Pay people for their time. GOV.UK says it is normal for members of the public to receive an incentive, that the amount depends on the participant and session length, and recommends giving it at the start of the session so no one feels they must answer a certain way to get paid. Research incentive budget covers how to set an amount.

Ask about what happened, not what they would do

GOV.UK's guidance on in-depth interviews recommends focusing on stories and real examples, asking open and neutral questions, and letting the participant do most of the talking. Interviews can run from 30 minutes to 2 hours; longer ones are harder to recruit for.

For the topper, build the interview around the last change:

• "Tell me about the last time you changed or added something to your dog's food. What was going on?"
• "Where did you look or who did you ask before buying?"
• "What else did you consider? Why that one?"
• "What did you pay, and how did that compare to what you expected?"
• "Is your dog still eating it? Why or why not?"

Avoid asking "Would you buy a topper that did X?" A hypothetical yes costs the person nothing, and a friendly interviewer can make one more likely. If you need to show a concept, do it at the end, after you have heard the real story. Customer interview questions has more wording to borrow.

Add the view from inside the industry

Consumers can tell you what they did. They usually cannot tell you what shelf space costs, which claims retailers will accept or how often similar products get returned. People who work in the category can.

For the topper, useful people might include a pet store manager who hears owners' questions daily, or someone who has marketed pet or food products. Their view complements consumer interviews but does not replace them, since they are describing other people's behavior. The retail marketing professionals and retail operations professionals directory pages list people with retail experience.

Instant Expert is suited to this industry side. Describe who you need, review the people it finds and send invitations; you pay only for calls that get booked. For recruiting large numbers of everyday consumers, a recruitment agency or panel is usually the better fit.

Turn conversations into findings

After each interview, write down the trigger that started the change, the options considered, the deciding factor, the price paid and whether the person stuck with it. Keep quotes attached to the person who said them.

After four to eight interviews, compare the notes. If most switches started with a vet's advice, that shapes where you market. If price rarely came up but palatability always did, that shapes the product. How to analyze customer interviews walks through this step.

Interviews show you reasons, not frequencies. If you need to know how many owners share a pattern, follow up with a survey or sales data; interviews versus surveys explains when each fits.