Ask any NRL fan who is the best try scorer so far this season and they will nearly always go to the leading try scorers list. They will nominate the player at the top of that list.
At the moment after 19 rounds, that player is South Sydney’s try-scoring machine, Alex Johnston. But is Alex Johnston really the best try scorer in the game this season?
Scoring tries is not a level playing field
Rugby league is a team game. Try scoring opportunities are created by teams for players, who are both fortunate enough to be in the right place at the right time and good enough to convert those opportunities into tries.
But these opportunities are not distributed equally across the field. Wingers receive far more try-scoring opportunities than say prop forwards or bench players. Also, the number of try-scoring opportunities will vary across different teams, in a way that may surprise you (more on this later).
So given that the opportunities to score tries are not shared equally across positions and teams, judging try-scoring ability from a single list of total tries scored by all players can be misleading and not all that useful.
A player playing in a position that doesn’t score many tries and playing in a team with lots of try-scoring talent around him may only score ten tries for the season. But this would be a very high achievement given the player’s limited opportunities.
How best to measure try-scoring ability?
Ideally, the best way to measure try-scoring ability would be to have a system that takes into account the number of opportunities players get and then produce a rating based on these opportunities and the tries they have scored from them.
The try-scoring rating system
This is what I have done, by developing a rating system based on how many tries a player has scored above or below the number of tries they would be expected to score, then expressed this as a percentage of their tries scored.
To come up with an expected tries figure for each I player I developed a formula, using data from the 2013 to 2020 seasons, based on the following factors:
• Game Minutes Played (GMP): 1 GMP = 4,800 seconds played (80 mins)
• Team Tries (TT): the total number of tries scored by the player’s team in the games the player has played in
• Position Value (PV): a numerical value of the player’s position based on the long-term percentage share of tries across all positions.
So, if Player X was expected to score 10 tries but had scored 12 tries then his try-scoring rating would be +20per cent (12 minus 10 = 2, 2 divided by 10 = 20per cent).
I deliberately excluded performance metrics that are closely related to a player’s try-scoring ability (eg line breaks, tackle breaks) because by only forecasting on opportunity, you get the players try-scoring ability largely determining the values above or below expectation.
Finally, I calculated some minimum cut-off points to weed out the “fluke” results; seven tries scored and eight game minutes played.
2021 Try Scoring Ratings (up to Round 19)
The block of cheese gets the chocolates.
Rnk Name Rating
1 Brandon Smith 107.22 per cent
2 David Fifita 82.62 per cent
3 Sitili Tupouniua 75.22 per cent
4 Viliame Kikau 71.93 per cent
5 Nathan Cleary 66.62 per cent
6 Angus Crichton 63.35 per cent
7 Tom Trbojevic 61.85 per cent
8 Isaiah Papali’i 61.66 per cent
9 Jahrome Hughes 61.23 per cent
10 Cody Walker 51.81 per cent
11 Daly Cherry-Evans 43.88 per cent
12 Alex Johnston 42.78 per cent
13 Matt Burton 41.91 per cent
14 Josh Addo-Carr 36.11 per cent
15 Reimis Smith 34.24 per cent
16 Clint Gutherson 30.63 per cent
17 Reece Walsh 30.27 per cent
18 Adam Doueihi 24.43 per cent
19 Matthew Dufty 21.78 per cent
20 Maika Sivo 11.42 per cent
21 Justin Olam 10.14 per cent
22 Jason Saab 9.69 per cent
23 Latrell Mitchell 6.64 per cent
24 William Kennedy 4.03 per cent
25 Reuben Garrick 4.02 per cent
Brandon Smith and David Fifita
Brandon Smith and David Fifita are exceptional players, playing in positions that historically don’t score as many tries as outside backs.
They have also played far fewer game minutes than wingers, who usually play the full 80 minutes. They are both great at breaking tackles and turning those runs close to the line into tries. This has translated into high try scoring ratings.
Negative try expectation
Some people may query players (like Brandon Smith) having a negative try expectation rating. This is because there is a constant in the formula (which is negative) and until players rack up enough opportunity data (GMP and TT) to overcome this constant, they will have a negative expected tries rating.
The role of team tries
When I first started developing this system, I assumed that the more tries a team scored, the more opportunities a player would get to score them. But after doing the analysis I discovered it was slightly the opposite case.
The Team Tries factor turned out to be a weak, negative factor for forecasting tries scored. The analysis showed that for every 100 team tries scored, the expected tries forecast for a player was reduced by 1.8 tries.
This basically means that good try-scoring players playing in weaker teams have a slight advantage over players in teams that score more tries (mainly because there is more competition for scoring tries).