At Waialae, the competition is always close

Si Woo Kim, 2023 Sony Open in Hawaii,Mandatory Credit: Kyle Terada-USA TODAY Sports
Si Woo Kim, 2023 Sony Open in Hawaii,Mandatory Credit: Kyle Terada-USA TODAY Sports /

There’s an odd characteristic to Waialae, which again hosted the Sony Open this past weekend in Honolulu. More than most any other regular PGA Tour stop, course conditions appear to dictate scoring.

It happened again this weekend at the event won by Si Woo Kim. His back-to-back closing 64s brought him home one stroke ahead of Hayden Buckley, with Chris Kirk two strokes behind in third.

At the championship level – which is a pretty relevant level for analysis – that was the big story. It was Kim’s second win in one calendar year plus one week; he is a former champion at this coming week’s American Express Championship in Palm Springs,

But a deeper analytical dive speaks to the role a course, such as Waialae, can play in influencing scoring on Tour.

It is an interesting characteristic of Waialae that year after year, its role in dictating scoring is substantially greater than most regular PGA Tour stops. It might be the weather, or it might be the course setup. That’s not clear from the data.

What is clear is that Waialae routinely presents Tour players with a disproportionate number of mood swings, if a golf course can have mood swings.

This weekend Waialae played to a pretty ‘normal’ course profile.

It so happened that this past weekend Waialae played to a pretty ‘normal’ course profile.

Among the 76 players who completed four rounds, the average score was 271.5, with a standard deviation of 4.03 strokes. Both of those are close to the five-year average at Waialae of 271.0 and 4.08 strokes.

Year to year,  however, “average” is not a word that aptly describes Waialae. Unusually large fluctuations in year-to-year performance are the norm.

Just since the 2019 event – that’s five events — the spread of the average four-round score at Waialae has been a massive 8.6 strokes, from a low of 268.4 last year all the way to 276.5 strokes in 2020. That’s way out of character with most regular Tour stops.

Compare the spread at Waialae with the other regular stops on the West Coast swing, excepting only Kapalua, a limited field invitation-only event. The table below shows the spread between four-round  average scores at each event since 2019.

Tourney (course)             Low        High       Spread

Sony (Kapalua)                  268.4     276.5       8.1

American Express (var.)  273.6     279.1       5.5

Farmers (Torrey)               281.5     286.3       4.8

WM (TPC Scottsdale)      274.1     278.5       4.4

ATT (various)                     278.5     283.3       4.8

Genesis (Riviera)              278.8     282.5       4.7

From year to year, Waialae has this unusual habit of changing from difficult to easy and back again. It’s not at all unusual for changes in course setup or weather to produce a one or two-stroke swing in year-to-year field performance. But the kinds of swings that occur at Waialae routinely exceed those that would normally be expected.

Interestingly, the result tends to be an even more intensely competitive field.

Statistically, the best way to assess a field’s competitiveness is to look at the standard deviation of the week-long results. As a simple rule, the smaller the standard deviation of performance within a Tour field, the deeper and more competitive we can say that field was.

At a standard PGA Tour stop, the normal first standard deviation spread is about 4.5 strokes. That is, we can expect about two-thirds of the field to shoot a score within 4.5 strokes, plus or minus, of the overall four-round field average.

At certain select events – the Majors, ironically, are notorious for this – the standard deviation spread tends to rise to or above 5.0, indicating fields that are actually less competitive than normal.

In the case of the Majors, that’s probably due to the processes used for determining entrants, which emphasize either selective invitations (the Masters) or an open competitive process (The Opens) that allows lesser-talented players to gain entry.

Neither of those processes is naturally conducive to deepening the field of qualifiers.

For purposes of deepening the field, the Sony Open is about as good as it gets. Since 2019, the average standard deviation of four-round scores at Waialae is just 4.08 strokes.  On the West Coast swing, only the AT&T Pebble Beach Pro-Am (4.21) even approaches that. The average standard deviation at the Amex is a quite normal 4.53, the Farmers is at 4.84, the WM Phoenix Open at 4.70, and the Genesis Invitational at 4.81.

Since 2019, there have been 30 West Coast Swing events contested. Seven of those 30 produced field standard deviations of 4.09 strokes or below, suggesting ultra-competitiveness. Those seven were:

1.       2020 Sony            3.39

2.       2019 ATT              3.56

3.       2022 ATT              3.81

4.       2023  Sony           4.03

5.       2010 Amex          4.06

6.       2021 Genesis     4.09

7.       2021 Sony            4.09

Next. Why Tournament golf is often an arbitrary game. dark

Of course, a non-mathematically minded person might arrive at the same judgment merely by glancing at the scores. For this past weekend, they reveal that 20 players finished within six strokes of Kim.

Still, it’s nice to know that the data supports the eyeball conclusion: When the Tour comes to Waialae, expect a Pier 6 brawl.