🏉 Do Coaches Matter?
A Data-Driven Look at Super Rugby 2025
Vern Cotter, Blues coach; Wikipedia
Rob Penney led the Crusaders to a thrilling victory over the Chiefs in the Super Rugby final, making him the standout coach of the season. Clayton McMillan, coaching the Chiefs for the last time, came a close second. But is that the full story?
Both coaches had squads stacked with talent. So the question arises: how much of their success was due to coaching, and how much was simply the result of having more All Blacks on the field?
📊 Star Power and Performance
This week, All Blacks coach Scott Robertson named his latest squad. Eight of those players came from the Crusaders—more than half of the starting 15 in the final. The Chiefs, despite losing, contributed 11 players to the squad. Together, these two teams made up 54% of the All Black selection.
Looking at the regular season (14 games before playoffs), there’s a strong correlation between the number of All Blacks in a team and its points differential (points scored minus points conceded over those 14 games). In fact, this relationship explains over 90% of the variation in team performance.
In short: the selectors did a solid job identifying the top talent, and that talent translated directly into results.
🧠 Coaching Still Counts
But coaching isn’t redundant. Fielding a star-heavy team doesn’t guarantee success. Players need to train their mental and physical skills, and teams must build cohesion. A great coach turns a group of individuals into a unit that’s greater than the sum of its parts.
🔵 The Blues Exception
One team stood out by outperforming expectations: the Blues, coached by Vern Cotter.
Despite having only four All Blacks, the Blues reached the semi-finals. During the season their defence was solid, but their offence lagged—they ranked 5th out of 6 in points scored, even behind the flamboyant Moana Pasifika (405 points vs. the Blues’ 377). Yet they exceeded their predicted net score based on All Black representation.
This marks the second consecutive year that the Blues have outperformed the “more All Blacks = more points” rule. Cotter’s coaching appears to be adding real value.
🏟️ Does Team Culture Matter?
Some pundits argue that team history and culture also play a role in ongoing performance. A strong legacy can attract better players, foster deeper training, and build a brand that sustains success.
To test this, I created a simple “history score” for each team: one point for reaching the semi-finals, one for the finals, and one for winning—across the three seasons since Super Rugby Pacific restarted in 2022. The Crusaders, Blues, and Chiefs dominated this metric.
When plotted against 2025 points differential, history explained 46% of performance. Not bad—but what happens when we combine history and All Black representation in a single model?
📈 Crunching the Numbers
Using the statistical software R, I ran a multiple regression with both variables – the number of All Blacks and the team’s history in the finals. R wasn’t thrilled—six teams is a small sample—but the results were clear:
History didn’t matter. Player quality did.
The number of All Blacks in a team was the dominant predictor of performance.
🧩 What’s Next for NZ Rugby?
If All Black-level talent drives success, how can we ensure a fairer distribution of that talent across franchises? And if coaching still adds value, how do we identify and replicate what top coaches like Vern Cotter bring to the game?
These are questions for New Zealand Rugby to consider as they look to make Super Rugby 2026 just as exciting.