What lesson does the Brexit vote hold for anyone conducting or contemplating fact investigation?

Don’t let confirmation bias muddy your thinking.

One of the key “Investigator’s Enemies” identified in my book, The Art of Fact Investigation, confirmation bias is what many of us tend to do when looking into an issue: we find what we expect (or want) to find.

The big money in last week’s British referendum was in favor of remaining within the European Union. It wasn’t just that large banks, corporations and the people who work there supported “Remain,” but that these people bet more heavily on their preferred outcome than those betting on Brexit.

The result? Even though opinion polls consistently pegged the race as very close, bookmakers in the UK put the odds of a Brexit victory at as little as 10 percent, according to the Wall Street Journal.

How could this be? For the simple reason that bookies like to balance their bets. Even though all voters in the U.K. got evenly weighted votes, bookies don’t evenly weight all bets. If you want to bet $400,000 on Remain and someone else bets $100 on Brexit, the odds will go heavily toward the Remain camp – whatever the polls say.

That may be what happened last week. So much money went against Brexit that those making — or in sympathy — with that outcome started to believe the odds and not the opinion polls.

How would this kind of skewed thinking work in an investigation?

Since all the information we have gathered about Mr. Jones is that he is a “New York guy,” we will not spend serious time looking outside New York to see whether he may have a litigation history or any commercial presence outside the city. We then could miss the apartment he quietly bought for himself in Miami two years ago, along with the companies he runs out of that apartment.

With confirmation bias, we might dismiss the idea of a Florida base because if he had such a thing, someone would have found it by now.

As with Brexit, we would assume that all of the “smart money’ was on one outcome (Brexit/New York) that we expect we will find.

Instead, a little smart inquiring (perhaps a database search nationwide on Jones, or a look at bet sizes for Brexit) would make us more informed and less beholden to our prejudices.

All people hold some form of prejudice when they begin an investigation. You need to have some pre-existing idea of where to look, since you can never look everywhere for everything. What we aim for is the judicious balance between inspired guessing and submitting to confirmation bias.