Rugby League history didn't start in 1998, but two big parts of Rugby League history did start that year - the Super League Grand Final and the NRL. I think that's a good enough reason to use it as the starting point for this look at the recent history of the two major Rugby League leagues.
A subject I've written about before is competitive balance. The theory goes that if the outcome of individual games, the season's league standings and the year to year title winners is uncertain and unpredictable then the league will be more popular and successful. It's a pretty reasonable theory. Like all theories, it isn't faultless and there are exceptions (most major association football leagues!), but it's fairly logical and robust.
So how do the biggest two modern day Rugby League competitions compare when it comes to competitive balance? Well, we probably all know the answer to that questions, but I've already made some graphs and tables, so lets have a look anyway.
Individual game outcomes
The proper academic ways for analysing short-run competitive balance can be complicated and time-consuming. I have a much less sophisticated and scientific way of looking at how competitive individual games were...looking at the difference between the winning team's score and the losing team's score.
When you look at the percentage of games that end with a one score or smaller winning margin, the picture is pretty much the same.
Unsurprisingly, when you look at the other side of the coin and count up games with wider winning margins, the NRL comes out as more competitive again.
A closing positive for Super League is that the playoff stage of the season has traditionally seen more close games and fewer blowouts than the same stage of the season in the NRL - when the top Super League teams play each other, the games are more competitive than the regular season. With an extended playoffs from the Super 8 format, we should see even more of this, which can only be good for the sport in the UK and Europe - as long as the Qualifier 8s doesn't detract from the Super League 8s too much as it did in 2015 on this score (see post from 26 November 2015).
The traditional medium-run measure for competitive balance is win-percent ratio, where the standard deviation of win-percents is compared to the idealised figure for the number of games played in the league. Put simply, the closer the win-percent ratio is to zero, the closer and more unpredictable that season was.
Like our first graph, no one year sees Super League be more competitive than the NRL, No NRL season has a worse win-percent ratio than than the Super League average win-percent ratio. 2007, again, is the most competitive of the Super League seasons. I've no explanation for why this is the case - the only notable difference for the 2007 season was the introduction of the Magic Weekend, which I can't see having any influence on competitive balance. One way this graph differs from the others is that the trends of both sets of figures shows Super League being on a stronger path to more balance, with the NRL also seeing a trend for falling win-percent ratios, but at a slower rate.
Once again, 2015 offers some promise of what the 12 team Super League can offer in terms of more equal competition - although we're yet to see what impact a promoted team might have to that, one way or the other.
Concentration of title wins is as good a way as any to assess long-run competitive balance. I don't a graph for this, I have a table.
At either end of the regular season standings you also see a bit more variation in the NRL than the Super League, more notably at the top than the bottom.
In Super League, the 'double' victory of leading the league and winning the final has happened 10 times in 18 seasons. In the NRL, it has happened six times. Huddersfield won a league leaders title after having picked up some wooden spoons in the past, but no Super League Grand Final winner has also finished bottom in the modern era. Six NRL sides have a wooden spoon along side a minor premiership in their trophy cabinet, and six have a spoon next to their Grand Final winning rings - seven if you allow the Western Suburbs part in the Wests Tigers joint-venture to count.
Has this post taught us anything? Maybe not, but at least its given us some evidence to support what we already thought - that the NRL is more competitive and unpredictable than Super League. But, hey, the trends show what is happening in Super League is moving us towards closer competition. That's good. Long may it continue.
P.s. Here's a table full of numbers, many of which informed the above graphs.