You might think that every single day of a golf major is as important as every other. You might be thinking that every shot is just as important as every other shot, and that”being clutch” doesn’t factor into a golf equation.

The data responds with a smirk that, in a sense, you’re completely wrong.

Half-way through the final major of the year, the field is packed at the top.

So who’s going to win the tournament? Based on the data I collected, we should really focus on which top ten player perform well today, because Saturday is actually the single most important day of a golf major, albeit by a very close margin.

I extracted data from the last five major golf championships, which amounted to more than 350 data points. My goal was simple: to see which individual day’s score was most highly correlated with a golfer’s final round score.

Here’s the brief synopsis of correlation (if you’re confused with the term; skip if you understand the term): it tells you how “related” two things are. For instance, the temperature is highly correlated with the amount of snow that falls. Temperature is not highly correlated with chewing gum sales. Perhaps sales go up during the summer, but for the most part, people are always buying chewing gum. Low correlation means that two events don’t really effect each other.

Here’s a simple way to think about how important each day is, on a scale of one to five. The following is based on an excerpt from Statistics for Dummies, Second Edition

  • 0.30. A weak uphill (positive) linear relationship = 1

  • +0.50. A moderate uphill (positive) relationship = 3

  • +0.70 or greater. A strong uphill (positive) linear relationship = 5

Based on these figures, we can compute that, on a scale of one to five, the first two days register as a two on this scale (see chart at top of page). This means, that they have a weak-to-moderate effect on a golfer’s final score. The third and fourth days, however, each have a correlation slightly above .6. This means that the third and fourth days have a strong-to-moderate influence on a golfer’s final score, as they are usually the best predictor and indicator.

The data knows best and the conclusion is clear: the Saturday and Sunday of golf majors are the days that turn players with potential into certified champions.