WHS - Understanding - PCC

Thank you for contacting Golf Link regarding the PCC (Playing Conditions Calculation) under the World Handicapping System (WHS).  

We would strongly suggest reading the article published by GA on their website which includes details on this and many other aspects of the WHS - https://www.golf.org.au/whs/

The PCC replaces (in sort) the previously used DSR.

PART B: Things that involve some change Item 14.

Daily rating system (PCC)
PCCs are permitted to range anywhere between -1 (ie easier conditions) and +3 (harder conditions).

Included below is further explanation from the GA Chief Statistician, the example used may assist you in understanding this aspect of WHS.

"Lets start by saying that the PCC formula is quite conservative, and it takes quite a lot to move the Daily Scratch Rating away from the official Scratch Rating, or equivalently, for the PCC to move away from zero. In fact, we have to be 95% confident that the result could not have been a statistical variation, ie one that could have turned up even if the conditions were normal.

This means that, yes, on some occasions the formula will fail to reflect the different conditions. This is the flip side of ensuring that on other occasions it doesn’t imply changed conditions which are not there.

Using the example below, the difference in average scores on the two days was about 2.9. When expected scores, player by player, are compared with actual, on the Wednesday, they were 2.5 average below expected. On Saturday, 0.1 better. The difference between the two days, 2.6, is what you might have expected from the “raw” 2.9 difference due to the higher average handicap on the Saturday.

But the PCC formula doesn’t rely solely on averages. It actually computes a table to calculate the proportion of the field that played better or worse than expectation by zero, 1, 2, 3, etc shots. Here is the table for the two comps: 

You can see that on Saturday, 52.0% of the field played to expectation or better; whereas on the Wednesday it was only 22.2%.

On Wednesday, 41.3% played one worse or better, and 55.6% played 2 worse or better.

If PCC was based on the median, or even the average of the scores to expectation, then Wednesday would have been at least a plus one PCC.

But PCC is based on a more conservative test, in the sense of being almost certain that the result could not have been achieved by random fluctuations.

This test, for a field of 63, says that less than 32.55% of the field need to be one worse or better to move the PCC to +1.

So on Wednesday, with 41.3% being one worse or better, the test is not met, and the PCC stays at 0.

In case it is of interest, the test is the at the red and green lines below, and, not surprisingly, gets wider as the field size decreases.

It is a tough test, as the red line is closer to +1 than zero; but the +1 needs to fall outside the “trumpet” to move the PCC off zero.

So, yes, the conservative PCC will not always reflect the conditions experienced, and when 41.3% of the field turned in a performance in the gale of only one worse (or better) than expected, the PCC stayed at zero."

We hope this clarifies PCC for you and as you can see from the article on the GA website and the example discussed by the Chief Statistician, it is designed to be harder to have a PCC other than 0.

To further assure you of its automated calculation correctly when scores are submitted to Golf Link, there have been no occasions since the inception of the WHS system where a PCC has had to be altered.