What to do when two experts disagree

When two experts disagree, check whether they described the same work under the same conditions before paying for another call. Start with your notes: what did each person say, when did it happen, and what did they personally do?

Keep their accounts separate from your explanation of the difference. GOV.UK’s analysis guidance makes that distinction between observations, findings and next actions.

Does “one day” mean the same thing as “six weeks”?

Here is a hypothetical example. You are planning how to support customers adopting a software product. One expert says onboarding takes a day; another says six weeks. You need to decide how much staff time to reserve and what launch date you can promise.

Check what each estimate includes. When does the clock start and stop? Is it time spent working, or calendar time including waits? Look for those details in the existing notes before assuming either person is wrong.

Suppose your notes clarify that the first person meant one day configuring a standard account after clean data arrived. The second meant six weeks from signing the contract to several departments using the product, including approvals and training.

They were measuring different work. Neither account establishes a typical duration for your customers. For staffing, you still need the work involved in your kind of setup. For a launch deadline, you also need to account for waiting on data, decisions and people’s availability. Averaging the two estimates would answer neither question.

What if the same fact is still disputed?

In the same example, suppose both people are now discussing the same product version, import route and settings. One says the file must contain a customer ID column; the other says that column is optional.

That is a specific claim you can check. If a current public import guide is available for that version, read its required-column list. It can establish what the provider documents. If the disagreement is about whether an upload actually succeeds without the column, a permitted test with nonprivate sample data could check that behavior under the tested conditions.

You do not need to carry out every possible check. Choose the one that answers the question you still have. Nielsen Norman Group’s guidance on using multiple research methods recommends looking at other sources or methods to address gaps in the evidence.

Give another call a specific job

Before choosing another person, finish this sentence: “I still need to find out…”

For the import example, that might be what happened when someone recently uploaded a file without the customer ID column using the relevant version and route. A person who handled that upload could describe the file and result. Another general opinion about whether onboarding is easy would leave the question unanswered.

Use the expert-selection guide to find someone whose work fits that missing detail. If the available evidence still does not settle the question, keep it open in your decision notes. A third person agreeing with one side does not, by itself, resolve the disagreement.