No luck for the Blues in NZ derbies
ANALYSIS: The Blues can’t seem to catch a break in Super Rugby derbies, but it is only a matter of time.
Statistically speaking, the Blues have been beyond unlucky against Kiwi teams over the past two seasons, dating back to their last victory over a New Zealand Super Rugby side.
That win came during the opening weekend of the 2016 season, a 33-31 triumph over the Highlanders in Auckland. The Blues have failed to win in 13 attempts against Kiwi sides since then, claiming just one draw (at home to the Chiefs) in those matches.
Eight of their 13 losses have been by a converted try or less.
The most they lost by was 15 points, twice, at the hands of the Chiefs and Crusaders during the 2016 season.
By judging Super Rugby teams by their points differential, rather than wins and losses, we get a better idea of the strength of teams and how fortunate or unlucky they are.
The Pythagorean Theorem was created for baseball by Bill James and modified for American football and rugby. It accurately translates points differential into an expected winning percentage.
Over the past two seasons, Kiwi teams have had an actual win percentage which closely resembles their expected win percentage.
Two of the biggest outliers were the 2017 Crusaders – who won 14 games when their points differential suggested they should have won 12 – and the 2017 Hurricanes – who won 12 games when their points differential suggested they should have won
13.
Where it gets particularly interesting is with the Blues, bottom dwellers in the incredibly difficulty New Zealand conference.
Since the start of 2016, the Blues have won 15 of 32 matches, to go with 15 wins and two draws. Based on their points differential, they’d be expected to have a 16th win over that time.
If you isolate the New Zealand derbies, the Blues have been particularly unlucky. With just one win in 14 attempts, the Blues have won just 7.14 per cent of their derbies during that period.
But with an average losing margin of just 6.36 points, less than a converted try, the Blues would be expected to have won five of their 14 matches.
The Pythagorean theory works on averages, so these things are expected to balance out over time. Winning matches by the odd point here and there isn’t sustainable, and should eventually see some results go the other way
Unfortunately for the Blues, it just hasn’t happened over the past two years.
While two wins against New Zealand opposition still wouldn’t have helped them in 2017, it could have seen them promoted to a playoff spot during the 2016 season at the expense of the Crusaders.
With the way Super Rugby is structured, those New Zealand derbies have much more significance than matches against other opposition. To be on the wrong side of fortune by four games in two seasons has a massive impact.
They have made up for it against other sides, winning 14 of 18 matches in two years, nearly three wins over what would have been expected.
A pair of blowout losses, to the Lions (43-5 in 2016) and the Sunwolves (48-21 in 2017) inflate that figure somewhat, but it still tells a story.
So, could anything deeper come into these figures? Are the Blues suffering a mental block when it comes to the challenge of Kiwi sides?
Are they simply raising their level on New Zealand soil, but dropping back down against the rest?
Whatever it is, lady luck will eventually come calling for the beleaguered Blues.