There is no shortage of statistics in the NRL these days, but which ones really matter? And what areas should your team be focusing on next season if they are to climb the ladder or challenge for the premiership? By analysing where 2015's most dominant clubs excelled this season, we can see what factors really matter when making a team successful in the modern game.

Looking back at the performances of the top four sides in the league in 2015 – premiers the Cowboys, grand finalists the Broncos, minor premiers the Roosters and fourth-placed team the Melbourne Storm – we've analysed five stats make a big difference to your team's winning chances, and three that don't. 

What matters:

Kicking game

The Cowboys, Storm and Roosters all finished in the top four for most kicks per game across the entire season, while the Broncos produced more kick metres a game than any other team – primarily coming off the boot of halfback Ben Hunt. Like a lot of stats, this one tends to reflect how dominant a team is across the board (a team that controls possession will have more kicking opportunities) but in the all-important territorial battle a good kicking game is obviously a key factor for a successful NRL side. All four of the league's best teams had at least one player possessing a dominant kicking game (Hunt at Brisbane, Johnathan Thurston at the Cowboys, Cooper Cronk at Melbourne and Mitchell Pearce and James Maloney at the Roosters).

Dangerous backline

Probably the most obvious key to being a successful footy team is the ability to break through defences and score tries, and the top three sides in the NRL were also the dominant attacking outfits in the league. The Cowboys notched more line breaks and scored more tries per game than any other team, with Dally M winner Johnathan Thurston creating a lot of those. The Roosters and Broncos ranked equal second for tries per game. Notably, all three sides had lethal attacking spines – Thurston, Michael Morgan, Lachlan Coote and Jake Granville for the Cowboys; Mitchell Pearce, James Maloney, Roger Tuivasa-Sheck and Jake Friend for the Roosters; and Ben Hunt, Anthony Milford, Darius Boyd and Andrew McCullough for the Broncos. 

Defence

"Defence wins premierships" is how the saying goes, and that mantra was proved right again this year. The four best teams in the league all sat in the top five defensive sides in the comp, with minor premiers the Roosters the frontrunners in this category. The Dragons were this year's fourth-best defensive team, but couldn't rival the top sides in attack and bowed out in the first week of the finals.

Strong forward pack and back three

In terms of run metres per game the Cowboys ranked first, the Roosters second and the Broncos fourth, with the Storm back in the back at eighth. This stands to reason when you consider the strength of each team's forward pack – the Cowboys' go-forward is led by Test stars Matt Scott, James Tamou and Jason Taumalolo; the Roosters have rep stars Jared Waerea-Hargreaves, Boyd Cordner and Aidan Guerra and a group of towering youngsters like Dylan Napa, Kane Evans and Sio Siua Taukeiaho; and the Broncos boast internationals Sam Thaiday, Matt Gillett, Corey Parker, Adam Blair and Josh McGuire. The Storm have arguably the best prop in the game in Jesse Bromwich but otherwise didn't have the star-power to match the three top sides.

Of course, it's not just the forwards who cart the ball up –the influence of the back three in kick returns is also vital. Roger Tuivasa-Sheck revolutionised the fullback role in his first full season in the position with a massive 241 run metres per game, with the Roosters the top team for kick return metres in 2015 and the Cowboys – led by the excellent Lachlan Coote – ranking second.

Ball control

The Storm might not have been the most thrilling team to watch at times but they did make fewer errors than any other side. The Cowboys ranked third for ball security, and the Broncos fourth. The value of controlling the ball is obvious – you deprive the opposition of possession in good attacking positions while also giving your own side the best chances of creating scoring opportunities. The Roosters are the outlier here, ranking 13th for ball control – largely because they chanced their hands with offloads much more than the other three top sides.

What doesn't matter:

Offloads

Last season the Penrith Panthers ranked first for offloads in the NRL. They were also one loss away from taking the wooden spoon. While offloads can be a great way to catch defences on the hop, they also lead to errors – and the most offload-happy teams are often also the most error-prone. The Panthers, Titans and Warriors produced the most offloads in the NRL in 2015 and they also ranked first, second and third for most handling errors. The Roosters were the fourth-biggest culprits in terms of errors per game, having been the only one of the top sides to try their hand at offloads this season (by comparison the Broncos ranked 12th for offloads, the Storm 13th and the Cowboys 15th). The Tricolours still won the minor premiership but it may have brought them unstuck in their preliminary final loss to the Broncos, when they made more offloads (17 to 11) but also coughed up a lot more errors (13 to five). 

Dummy-half runs

Our four top teams had wildly different numbers in this category, with the Storm running the ball from dummy half more than any other team (led by Kangaroos hooker Cameron Smith), while the Roosters scooted from dummy-half the least in the NRL. The Broncos ranked third for dummy-half runs per game, with the Cowboys were 11th. With no obvious trend herre, the tendency to dart from dummy-half obviously doesn't make a significant difference to a team's overall results.

Tackle breaks

The ability of an individual player to beat a defender one-on-one doesn't necessarily lead to their team being strong in attack. Of course it doesn't hurt; the Roosters ranked first for tackle breaks this season, led by Roger Tuivasa-Sheck, Daniel Tupou and Michael Jennings, and also scored more points than any other side. But the Cowboys ranked just sixth in this stat, while the Broncos were 12th and the Storm 15th. By comparison, the Wests Tigers had the best tackle-breaking back (James Tedesco) and forward (Martin Taupau) in the league, and still finished second-last, while the Dragons ranked fourth for tackle breaks but 15th for points scored. Having a creator like Johnathan Thurston in your side who can put players into gaps is obviously a better weapon then having a ball-runner who can crash through an attempted tackle.

What does this mean for the competition in 2016? Check back later this week as NRL.com looks at the clubs who could become premiership contenders next season.