Look for a partner who studies what people do, not just what they say, and who can show you a decision their research changed.
Most research asks people for their opinions. Behavioural research looks for evidence of what they actually do. The two often disagree. People say they compare options carefully, then buy the first one that feels safe. They say they read the instructions, then skip them.
Behavioural evidence comes from watching people in context, studying records of what they did, testing what they choose when given real options, and following them over time.
For Shadforth Financial Group, we didn't only ask clients what they wanted from financial advice. We secret shopped competing firms online and in branch, and worked through 25 client case files to see where real clients had hesitated or dropped out. That showed patterns no interview would have surfaced.
In building products, the people who say they choose a product are often not the people who decide. For a lightweight concrete panel brand, we went straight to the installers who fit the product, because what trades find easy to fit shapes what gets used. See Researching How Australia Builds.
"How do you handle bias?" A good answer covers who they recruit (including unhappy and hard-to-reach people), how they avoid leading questions, and how they check findings against other evidence.
"Can you show impact from past work?" A good answer names a decision the research changed and what happened afterwards.
"How do you work with our team?" A good answer invites your people into the sessions, so the findings don't have to be sold to them later.
There is no single best. The useful question is who has worked inside your constraints before. Behavjōr is a Sydney behavioural research and design consultancy. Our research is led by a qualified psychologist, and we work across enterprise, government and education. You can see the method applied in our behavioural research and strategy practice, and in the Heidelberg case study, where behavioural research reshaped a concrete delivery service.
Related: Behavioural research and strategy and the Heidelberg case study.