It is human nature to want to be able to make the best decisions.
And usually this leads to advice about making sure you have enough information for a thorough analysis, weighing up all the factors before then being able to be confident in a decision you make.
The problem is that research shows that having more information does not necessarily lead to better quality decisions.
Even worse, having more information is likely to make you think and feel like you’ve made a better decision, when in reality it was no better than a guess.
An excellent piece of research by Slovic and Corrigan (1973) proved this.
They worked with 8 professional Handicappers, whose job it was to predict the outcomes of horse racing. Horse racing is a field where there is a huge amount of information about previous performance publicly available, yet the outcome of any new race is a gamble.
The Handicappers were asked to predict the placing of horses for 40 races, and were given a checklist of 88 potential information categories about a horse’s past performance they could choose from before placing their bets. They were originally told they could only choose 5 of the 88 pieces of available information which they wanted to see (example image shown below).
After the bettor had placed their bets, they were told they should choose again, but this time with 10 pieces of information of their choice rather than just 5.
And then two more times, this time with any 20 pieces of information they wanted, and finally with 40 different pieces of information they wanted (as seen in the example image below):
The important thing was that after placing each bet, the bettor was also asked how confident they were that their prediction would come true.
These were after all professional gamblers, who knew that not every bet would pay off, but should also have a gauge on whether a bet was more likely than average to succeed.
When the bettors only had 5 pieces of information to work with, they were only about 19% confident in their predictions.
Unsurprisingly, when they got more information, they felt more confident in their predictions. Once they had access to 40 pieces of information, they were suddenly more than 30% confident in their predictions.

accuracy does not rise with confidence
However, no matter how many pieces of information they had, their accuracy stayed at around 17%. Their performance did not improve, even though they were confident it would.
This shows that having more information doesn’t necessarily lead to making better quality decisions, even though it might feel like it.
So if you or someone on your team keeps wanting to see more information or evidence before making a decision, perhaps help them understand that past a certain point it won’t make the eventual decision any better.
Sometimes it is more effective to get going sooner with less information.
Nick Skillicorn
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