STATS DROP: Round 15, 2023

State of Origin caps, Form Elo, Pythagorean expectation, 2nd order wins, WARG and TPR for NRL and Queensland Cup

Jun 14, 2023

Welcome to Stats Drop, a weekly inundation of rugby league numbers.

A couple of years ago, I looked at which clubs had had the most State of Origin caps. That yielded one of my favourite pieces of esoteric rugby league trivia that the Panthers took until 1995 to have as many State of Origin caps as Wynnum Manly had had by 1987.

Now that Redcliffe have joined the NRL, and Hamiso Tabuai-Fidow and Tom Gilbert are the first Dolphins to have been selected for Queensland since Greg Conescu and Bryan Niebling in 1987, I thought it was time to update the dataset.

Broadly, Queensland’s two strongest periods in Origin were the 80s, when there were multiple BRL clubs to draw upon, and the 10s, when there were multiple NRL clubs and the Storm to draw upon. It’s clear that we’re not returning to a 90s and early 00s level of Broncos dominance any time soon for a variety of factors (e.g. enforcement of the salary cap, other potential employers for players, generalised cheating by other clubs, etc) and that’s probably for the best from a whole of state perspective. Brisbane’s selections have at least bounced back from their 2020 wooden spoon lows to return to something close to the recent historical trend.

Interestingly, the club that is neither in Queensland nor in New South Wales alread has the fourth most all-time caps. The Storm will likely never be able to catch the Broncos but are 27 caps adrift of the Roosters’ second place. Despite the obvious geographical conundrum and not entering the competition until nearly 20 years into the concept, Melbourne’s players have been a noticeable presence in the Origin arena. That this has mostly come through Queensland is no accident, as is the popularity of the Storm north of the Tweed, although it can also be partly explained by their asterisk seasons.

Like most clubs, the Cowboys’ selections rise and fall in line with their performance on the field, peaking around 2005 and then the mid-10s Thurston-led North Queensland sides. It’s difficult to say whether the Titans’ caps mirrors their performance because the Gold Coast are more often poor than not. It’ll be interesting to monitor how their respective contributions change with their pathways plans.

Trivia

The selections of Gilbert and Tabuai-Fidow have pushed the Dolphins (44) past the Steelers (43) into 20th place. There’s a chance they pass the Wests Tigers (48) in the next couple of years into 19th. Then begins the chase to Wynnum Manly’s 70 caps.
The BRL’s Big 8 clubs have a combined 180 caps, which would be 12th on the all-time list, between St George Illawarra and Cronulla. That’s not bad for a bunch of clubs that no caps for 35 series and are considered irrelevant to the history of “the game”.
Between 1980 and 1987, there were 300 Queensland Origin caps. Of those, 177 were occupied by BRL players, or an average of 59%. That peaked in 1983 when only ten caps were given to interstate players and the remaining 35 were held by local players. I’ll wait here while you look up the results of that series and ponder whether the received narrative about the relative strengths of the Brisbane and Sydney competitions is accurate or simply based on the last available example.
Rohan Hancock was picked out of the Toowoomba competition to play for the Maroons in the 1980, 1981 and 1982. Greg Conescu was playing for Brothers Gladstone in 1984, the last player to be selected for Queensland from the bush.
17 years before Alfie was brought home for one last mission, Bob Kellaway was selected from Bradford Northern to play in game 3 of the 1984 series.

NRL Stats Drop

Scroll to the end for the explanatory notes or visit How It All Works.

Queensland Cup Stats Drop

Explanatory notes

Elo Ratings

Elo ratings are a way of quantitatively assessing teams, developing predictions for the outcomes of games and then re-rating teams based on their performance, home ground advantage and the strength of their opposition. Form Elo ratings are optimised for head-to-head tipping and tend to reflect the relative strengths of each team at that particular point in time, although there are many factors that affect a team’s rating.

Pythagorean Expectation and Winning Percentage Comparison

The black dots on the winning percentage comparison are each team’s actual win-loss record to this point in the season. The coloured dots represent what the stats say about the team’s underlying performance, i.e. how many games they should be winning. Wins and losses are binary and can be prone to good and bad luck in a way that other stats that correlate to wins are not, so we have other metrics to help see through the noise to good teams, rather than just good results. While each metric has strengths and weaknesses, it helps paint a more complete picture of team performance.

Pythagorean expectation (gold) relies on points scored and conceded by estimating a team’s number of wins based on their for and against. Where there is a deviation between a team’s actual record and their Pythagorean expectation, we can ascribe that to good fortune, when a team wins more than they are expected to, or bad fortune, when a team wins less than they are expected to. 2nd order wins (silver) relies on metres and breaks gained and conceded. Elo ratings (maroon) rely on the margin of victory and strength of opponent.

Dots should tend to gravitate towards each other. If a team’s dots are close together, that means their actual results are closely in line with their underlying metrics and represents a “true” or “fair” depiction of how good the team is. If a team’s coloured dots are clustered away from their actual record, then we should expect the actual and the coloured cluster to move towards each other over time.

If the black dot is well above gold, that team is suffering from good fortune and may mean regress to more typical luck in the future (vice versa also holds). The silver dots will tend to hover around .500, so if gold is between silver and .500, the team could have an efficiency issue. On the balance, I would expect more often the actual percentage will move towards the cluster but the opposite is also possible.

Player Leaderboards

Production the amount of valuable work done by a team as measured in counting statistics that correlate with winning. These statistics are converted to a single unit called Taylors. Taylor Player Ratings (TPR) are a rate metric that compares an individual player’s production, time-adjusted, to that of the average player at their position, with a rating of .100 being average (minimum 5 games played). Wins Above Reserve Grade (WARG) is a volume metric that converts player’s production over a nominal replacement level into an equivalent number of wins they contribute to their team.

Team Strengths

A chart that tabulates each team’s WARG, both as a team total and broken down into platoons by listed position, to identify each team’s relative strengths and weaknesses.

The WARG is the sum produced at the position, not by specific players, e.g. if Kalyn Ponga produces a total of 1.5 WARG comprising 1.0 WARG while named at fullback and 0.5 WARG named at five-eighth, then the WARG produced while named at fullback will be added to the 1-5 platoon and the WARG created while named in the halves will be added to the 6+7+9 platoon.

The top team in each category is rated 100, the bottom team is rated 0 and every team in between is scaled accordingly.

Team Efficiencies

This table compares the SCWP produced and conceded by each team (a product of their metres and breaks gained and conceded) against the actual points the team scores and concedes to measure which teams are most efficiently taking advantage of their opportunities. A lack of efficiency here could be the result of bad luck and poor execution - sometimes you have to watch the games.

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