I'm reading "The Lost Lion," a mammoth biography of Winston Churchill. Right now we are between wars and Winston is a back-bencher. There was a time during the thirties when he was done for, a complete has-been. He had a stellar early career and was the youngest first lord of the admiralty. But because of his impolitic nature and outspoken beliefs, during this period he was widely thought to be finished.

But he had some great advantages during his time in the wilderness. Not the least of which is that he was out of the government during the time when the government's policy was appeasement. But yet he still had enormous prestige, and even more importantly private access to data on Germany's war build up and England's defense status. Perhaps because of this data, he knew earlier than anyone else Germany's true aims and England's lack of preparedness.

I could stop the analysis right there and go on about the importance of hard data for guiding decisions, but the story is considerably more interesting than that. The reason is that the Prime Minister, Baldwin, had access to most if not all of the same information that Churchill had but did not form the same conclusion.  That's the peril of data. It doesn't actually make decisions for you. Furthermore, I'm fairly confident that Churchill would have formed the same opinion about Hitler even if he didn't have access to the data. Given that this same dynamic plays itself out over and over, you can be forgiven for wondering if data actually helps at all.

The first step to escaping this conundrum is simply to recognize that data doesn't make decisions, people do. Once you realize that you are free to make decisions that seem to contradict the data available, you tend to be much more receptive to gathering more data and working through the implications. Ironically, it also helps  to keep you from making one of the bigger mistakes that you can make with data analysis. It helps you avoid explaining away unexpected numbers. When it became clear that the Nazi's Luftwaffe exceeded the RAF in terms of number of planes and number of pilots, Baldwin made the claim that England still had parity with Germany because the British pilots were better trained. Baldwin would have been more honest to accept that Germany had exceeded England's air power. He was still free to state that the policy of England would remain peace at any cost and that he would not get trapped in an arms race. This freedom would have provoked a more honest discussion and perhaps less credibility for appeasement.

The risk of explaining away data is so pervasive that it warrants some additional comments. All data has problems. In science, there is always more data to gather and more experiments to run. And yes, early reports can be wrong and scientific consensus can be overturned. But watch what happens as more data comes in. Look at which viewpoint requires creating ever more elaborate explanations. If you simply avoid ever explaining away data regardless of its implications, you can prevent yourself from falling into the trap of arguing about the data rather than the decision.

This pitfall has an interesting flip-side. People often lack of data as a way of deferring decisions.  They table an issue to gather more data. As often as not, the issue isn't discussed again and the data isn't gathered. The lack of data is being used as an excuse. But once you remember that people make decisions, then data can never be blamed. One simple way to avoid this trap is to formulate decisions up-front based on hypothetical values for the data you plan to gather. In other words, let's imagine you had this elusive data and it was X, what decision would you make? What if it were Y? If the decision is the same in both cases, why go through the trouble of gathering the data? If you still can't make the decision, even with hypothetical data, are you sure that you it's the right data?

The best use of data is that it is a tool to help you kill your intuition. It's the voice whispering in your ear and occasionally the hand slapping you in the face. It's not rhetoric and it's not a story. It's our only way to connect with cold reality.