You're Reading: Playing the Percentages in Golf (with Calculator)

Playing the Percentages in Golf (with Calculator)

-- February, 04 2023 at 12:38 pm ET

The approach to a golf green with a yellow flag. Overlayed on top of the golf hole is a graphic that depicts the possible ways to play the hole.
Course management starts on the tee. Club selection will determine the likelihood of subsequent shots and outcomes

It’s not always your golf swing, short game, or even putting stroke that holds you back from shooting your best scores. Over the course of 18 holes, course management decisions will have some effect on your scorecard. Typically, the concept of poor course management on the golf course is associated with golfers choosing riskier shots and not playing safe. While this is true, the goal should be to achieve the smart play or the shot that result in the best overall probability to make the lowest score on a given hole.

Playing the Percentages in Golf

Put simply, playing the percentages or playing the percentage shot in golf is choosing a given shot type, approach, strategy, etc., that has the highest likelihood of success.

For instance, while we do not always listen to reason in the moment, the shot from within the woods over the trees and over a pond onto the green has a low likelihood of success. What’s more, in this case, with the threat of penalty from the pond, the odds are high that the result will be a disastrous score for that hole. Instead, the shot with (hopefully) a far greater chance of success is punching out to the fairway and proceeding to finish the hole from there.

This is an obvious example, and certainly in golf there are situations that involve options with considerably more uncertainty. Furthermore, playing the percentages and factoring the odds into your course management, should extend beyond an isolated shot consideration, particularly when the right decision is not as clear as it is in the above hero-or-zero scenario.

Why to Avoid Isolated Golf Course Decisions

The issue with making isolated decisions is that while they might produce a safe alternative and avoid a big number, they risk the mistake of leaving something on the table. Furthermore, it is not always the safe play now that will serve as the safe or smart play for the entire hole.

To put this to extremes, imagine the reliability of hitting your pitching wedge off the tee. You will almost certainly hit more fairways and avoid the danger off the tee. However, this is obviously not the correct strategy as it makes any effort to achieve a green in regulation or even being greenside in regulation difficult.

Risk-reward holes by design are intended for either a riskier play or a safer play that avoids the hole’s danger. As golfers, the risky shot with greater potential reward is more enticing but this is not say that it is not the correct approach. A lot depends on the situation, weather conditions, and your comfortability with the shots you have to pull off. Leading a tournament or a match provides an additional consideration.

Enter Conditional Probability

So, where does this leave us? To truly make an educated and accurate course management decision, we must analyze a hole’s strategy 1) among the different alternatives from the tee, 2) the alternatives that extend from each tee shot option, 3) the shot alternatives that extend from those shots and so on.

For example, on a par 4, you consider hitting either your driver or 3-wood. Let’s say that 15% of the time you will pull/hook your driver, 40% of the time you will push/slice, and the remaining 45% of the time you will hit your drive down the middle. Assuming slightly better accuracy with your 3-wood, the respective percentages may be 10% hook/pull, 30% push/slice, 60% down the middle.

So far, it sounds like 3-wood is the better option.

Now, after hitting your driver, let’s say that from the left or right woods, 75% of the time you will just punch out and the other 25% of the time you will go for the green, hitting the green 10% of the time and missing 15% of the time.

From the fairway with your driver, you will hit the green with your first shot 80% of the time and miss the green 20% of the time.

Since 3-wood will leave a longer approach, the same shots will have different and worse probabilities: from the woods, punch out 80% of the time, hit the green 5% of the time, miss the green 15% of the time. From the fairway, after hitting 3-wood, you will hit the green 65% of the time and miss the green 35% of the time.

After the punch out, for both the driver and 3-wood scenarios, you will hit the green 90% of the time and the other 10% you will take two shots. When failing to hit the green from the woods, you will hit the green 50% of the time and the other 50% of the time it will take you two shots to hit the green.

With this information, conditional probability and expected value are needed to determine the best play on the hole.

Conditional Probability is defined as the likelihood of an event or outcome occurring, based on the occurrence of a previous event or outcome.”

Using the definition of conditional probability, we need to define our events and their associated probabilities.

In our case, the different events are:

  • Hitting the Fairway
  • Hitting into the Woods
  • Hitting the Green from the Fairway
  • Punching Out
  • Hitting the Green from the Woods
  • Hitting or Missing the Green after Punching Out
  • Etcetera

The ideal scenario is hitting the fairway and then the green. With driver, the odds are 45% of hitting the fairway and 80% of hitting the green from there.

Put differently, of the 45% of the time that driver finds the fairway, the next shot will find the green 80% of the time. In mathematics, “of” means to multiply.

Therefore, before playing a shot on the hole, the odds of hitting the green in two is .8 x .45 = .36 or 36%.

A similar process must be computed for all the other scenarios and child scenarios (a child scenario, e.g., would be hitting or missing the green after punching out from the woods).

Using Expected Value

To calculate an actual score (or average score) from the Driver or 3-Wood alternatives, we must use expected value.

Expected Value is the weighted average of all possible outcomes.”

The following are the expected values or expected strokes for hooking left, slicing right, and down the middle when hitting driver off the tee along with the initial odds of hitting each:

  • Hooking Driver Left (15% of the time) – 3.05 strokes
  • Slicing Driver Right (40% of the time) – 3.05 strokes
  • Hitting Driver Down the Middle (45% of the time) – 2.2 strokes

Note: Slice right and hook left have the identical expected number of strokes. This is strictly due to the fact that we treated the shot options from both scenarios identically. This can be fine-tuned or tailored to a specific hole or any other factors.

To be clear, these are the average (weighted average) number of shots required to hit the green including the stroke used to hit the tee shot.

Consequently, to calculate the expected value of selecting driver off the tee, we use the following calculation:

Expected Value Calculation for Driver
Expected Strokes = (3.05 x 0.15) + (3.05 x 0.15) + (2.2 x 0.4) = 2.6675 strokes

Similar calculations were performed for the child scenarios of each tee shot to arrive at the expected strokes used above.

Note: For the sake of simplicity, the above does not consider putts. If you want, you can simply assume two putts. However, more practically, we know that if we hit driver and are closer to the green, we not only have a better chance of hitting the green but will likely leave a shorter (and more makeable) putt than when we are approaching the green from a further distance. To be complete, the odds of a one putt, two putt, and three putt should be determined and entered into the overall calculation.

An Easier Method

It should quickly become apparent that the process of calculating conditional probability is cumbersome to say the least. Instead, calculations such as these are much better suited for a computer than a human. That is why you should use Golf Surfer™’s conditional probability golf calculator shown below.

Top Level Scenarios:
    Add New Top Level Scenario

    The video tutorial will indicate how to use the calculator. For further questions, refer to the guide towards the end of the article. Ultimately, though, you can extend the scenarios as much as you want and tailor the shot types to the particular hole you are playing. Obviously, it works best when you know the probabilities of each shot based on your game and ability.

    Conditional Probability Calculator Demo Video

    Practical Use

    Okay, so using the calculator to determine the best possible strategy is great for planning out your round beforehand. During the round, though, the average golfer will not be capable nor benefit from performing such an in-depth calculation.

    Nevertheless, this same thought process should be practiced. Do not worry about deciding between club selections based on a difference of one hundredth of an expected stroke. However, make an approximate calculation that you know you can trust the majority of the time.

    One Shot at a Time

    In winning interviews on the PGA tour, it is typical for the golfer to comment on his playing one shot at a time and how that helped him in his victory. Staying present is important. A big number can crop up at any time during a round of golf. This is true for professional golfers and amateur and recreational golfers alike.

    Even the pros of the DP World Tour struggle with costly mistakes

    Thinking ahead to the finish line and failing to concentrate in the moment can come back to hurt you.

    However, considering your strategy for the entire hole should be included for every shot even when focusing on the present shot at hand. Making these considerations is important for two reasons.

    First and foremost, if done properly with an accurate portrayal of a golfer’s ability and tendencies, the best shot will be chosen more often. Second, while this may depend on the type of player and personality you have, your confidence in the shot you select and your commitment to the shot should improve knowing that you carefully and rationally weighed the expected or likely score from each possible shot. You will not have to second guess whether the shot you hit now will place you in the optimal position for your next shot.

    In the end, you can achieve a one-shot-at-a-time mentality while also playing the percentages.

    Quick Guide Reference for Conditional Probability Golf Calculator

    Go Back to Calculator

    Understanding Key Terms

    • The calculator greatly simplifies the process of calculating the expected number of golf strokes based on the expected strokes of its child scenarios
    • A child scenario is a shot option that occurs after the play of an initial or parent scenario: Going for the green after hitting driver off the tee is a child scenario
    • Top-level scenarios do not have probabilities or strokes because they are club selections or other course management decisions you have full control over. They should indicate an overall strategy
    • After you choose a top-level scenario, the outcome is related to probability as you no longer have full control. For example, after you choose a top-level scenario such as hitting driver, controlled driver, or 3-wood, the probabilities of the child scenarios will be dictated by your history of your misses and successes for each of those shots

    Using the Calculator

    • To start, enter a shot choice off the tee. This a top-level scenario and will only require a shot type
    • In the next screen, enter a child scenario associated with the top-level scenario
    • After returning to a parent scenario with the “Previous” button, you will see all direct child scenarios added to that parent scenarios listed under “Child Scenarios:.” Click on the list items to navigate into them. ES stands for the expected strokes of each child scenario and P stands for the probability you have assigned
    • Top-level scenarios require that their direct child scenarios have a combined probability of 1. Until they do, their expected strokes will be “Missing” or 0

    Understanding Error Messages

    • Deleting a scenario will result in all child scenarios to also be deleted. Try using the Edit feature instead
    • ”Cummulative Probability Cannot be greater than 1”: cummulative probability is the sum of the probability of each direct child scenario. It does not make any sense for the possible options to have a combined probability that is greater than 0 so it is disallowed

    Appendix: Full Calculation of Expected Strokes

    Solve for Expected Strokes for Hook Left Top-Level Scenario:
    Punch Out >> Hit the Green
    Probability = (0.90) = 90%
    Strokes Required = Hit the Green (1) = 1 Strokes
    Punch Out >> Take Two More Shots to Hit the Green
    Probability = (0.10) = 10%
    Strokes Required = Hit the Green (2) = 2 Strokes
    Punch Out (75% Assigned Chance) Expected Strokes
    Expected Strokes = Punch Out (1) + (0.9) x (1) + (0.1) x (2) = 2.1 Strokes
    Go for the Green from the Woods (25% Assigned Chance)
    Hit the Green from the Woods
    Probability = (0.10) = 10%
    Strokes Required = Hit the Green (1) = 1 Strokes
    Miss the Green from the Woods >> Hit the Green
    Probability = (0.50) = 50%
    Strokes Required = Miss the Green (1) + Hit the Green (1) = 2 Strokes
    Miss the Green >> Take Two More Shots to Hit the Green
    Probability = (0.50) = 50%
    Strokes Required = Miss the Green (1) + Take Two More Shots (2) = 3 Strokes
    Miss the Green from the Woods Expected Strokes
    Expected Strokes = Miss the Green (1) + (0.5) x (1) + (0.5) x (2) = 2.5 Strokes
    Hook Left Expected Strokes
    Expected Strokes = Hook Left (1) + Punch Out: (2.1) x (0.75) + Hit the Green from the Woods (1) x (0.10) + Miss the Green from the Woods (2.5) x (0.15) = 3.05 Strokes
    Solve for Expected Strokes for Slice Right (same as Hook Left in our case) Top-Level Scenario:
    Punch Out >> Hit the Green
    Probability = (0.90) = 90%
    Strokes Required = Hit the Green (1) = 1 Strokes
    Punch Out >> Take Two More Shots to Hit the Green
    Probability = (0.10) = 10%
    Strokes Required = Hit the Green (2) = 2 Strokes
    Punch Out (75% Assigned Chance) Expected Strokes
    Expected Strokes = Punch Out (1) + (0.9) x (1) + (0.1) x (2) = 2.1 Strokes
    Go for the Green from the Woods (25% Assigned Chance)
    Hit the Green from the Woods
    Probability = (0.10) = 10%
    Strokes Required = Hit the Green (1) = 1 Strokes
    Miss the Green from the Woods >> Hit the Green
    Probability = (0.50) = 50%
    Strokes Required = Miss the Green (1) + Hit the Green (1) = 2 Strokes
    Miss the Green >> Take Two More Shots to Hit the Green
    Probability = (0.50) = 50%
    Strokes Required = Miss the Green (1) + Take Two More Shots (2) = 3 Strokes
    Miss the Green from the Woods Expected Strokes
    Expected Strokes = Miss the Green (1) + (0.5) x (1) + (0.5) x (2) = 2.5 Strokes
    Slice Right Expected Strokes
    Expected Strokes = Slice Right (1) + Punch Out: (2.1) x (0.75) + Hit the Green from the Woods (1) x (0.10) + Miss the Green from the Woods (2.5) x (0.15) = 3.05 Strokes
    Solve for Expected Strokes for Down the Middle Top-Level Scenario:
    Hit the Green (80% Assigned Chance)
    Probability = (0.80) = 80%
    Strokes Required = Hit the Green (1) = 1 Strokes
    Take Two Shots to Hit the Green (20% Assigned Chance)
    Probability = (0.20) = 20%
    Strokes Required = Take Two Shots (2) = 2 Strokes
    Down the Middle Expected Strokes
    Expected Strokes = Down the Middle (1) + Hit the Green: (1) x (0.8) + Take Two Shots (2) x (0.20) = 2.2 Strokes
    Solve for Expected Strokes for using Driver:
    Expected Strokes
    Expected Strokes = Hook Left: (3.05) x (0.15) + Slice Right (3.05) x (0.40) + Down the Middle: (2.2) x (0.45) = 2.6675 Strokes
    Show More

    Wrapping It Up

    While this article may have seemed like a little bit of a math class, hopefully everything was simple enough to grasp. Making a thorough analysis of your abilities and appropriate strategies based off them will improve the mental and course management aspects of your game.

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