As the Roosters' Cooper Cronk trudged off to the sin bin in last year's NRL grand final, the match lay poised.

The favourites were buckling and faced 10 minutes against the surging Raiders, one man down.

After Jarrod Croker made the score 8-all with a penalty goal, the most important 10-minute passage of the season unfolded.

From the kick-off, however, the Roosters maintained good field position and the Raiders enjoyed just a single venture inside the 20-metre line.

Seconds before Cronk returned, that foray ended with a turnover centimetres from the line.

It was the closest the Raiders would come to scoring again.

Thirty minutes later they were losers, having been unable to register another point after their fateful decision to take the two.

The eternal conundrum

'Taking the two' refers to when an attacking team is awarded a penalty and chooses to kick for goal (worth two points) instead of keeping hold of the ball and going for a try (worth four points along with the opportunity for a two-point conversion).

It's the classic conundrum of risk versus reward.

While a game ebbs and flows with momentum shifts and fatigue, a good team takes on average about 10 play-the-balls inside the attacking 20-metre line to score according to NRL Stats.

That means a try — worth up to six points — is a long-shot.

On the other hand, the penalty goal is a highly likely two points. Most clubs average around four successful kicks out of five and locations for attempts at penalty goals are usually some of a kicker's easiest kicks.

Against the Roosters, Raiders coach Ricky Stuart took the two.

Coach Ricky Stuart could not quite engineer a Raiders victory. ( AAP: Brendon Thorne )

But to take the tap and keep the pressure on against 12 Roosters was about as good an opportunity Canberra would get all night to cross again.

It's the kind of decision that divides fans and provides a glimpse into the mindset of coaches.

Wayne Bennett is known for playing it safe and going for goal. Paul McGregor has copped heat for taking the two. Kevin Walters isn't a fan.

In basic maths, every time a team takes the two, it sacrifices the chance for four or six.

On 163 occasions in the past five seasons, a team has potted the two and gone on to lose the game by four or less, or missed the kick and lost by six.

But the opposite is also true.

In 106 matches, the winning team was victorious by two points or less, having taken the two earlier on.

When to take the two

Whether to go for it or not depends on many factors. The score. The time left. The danger of your team's attack. The competence of the defence. The calibre of your kicker. The conditions. The referee.

So when should a team take the two, and when should they opt for the quick tap?

Accenture data scientist Joe Cleaves was inspired to analyse penalty goal probabilities by the conservative play of Wayne Bennett. ( ABC News )

Joe Cleaves and colleagues at professional services firm Accenture have modelled just that.

As part of the NRL 'DataJam' competition held during the off-season, his team grabbed actual decisions made by coaches in over 400 games and injected them into a machine-learning algorithm.

"The inspiration behind the analysis was my team St George and their great [Wayne Bennett-coached] premiership win in 2010 always taking the two whenever they had the opportunity," Mr Cleaves says.

He says the analysis found that it's usually wise to take the two points, but additional considerations should not be ignored.

"There are other factors as well at the fatigue of their players, and the scoreboard as well," he says.

"If you're four points behind you might want to go for the try, even if that's the option that wouldn’t usually lead to more expected points."

Controversial refereeing decisions were in the grand final spotlight, but the Raiders failed to capitalise on opportunities. ( AAP: Joel Carrett )

Helping coaches with 'gut feel' calls

The team created a tool for coaches that delivers immediate advice when the decision about whether to take the two needs to be made.

They hope it might one day find its way into coaches' boxes.

Andrew Gray took over as high performance manager at Wests Tigers in the off-season. ( ABC News )

Andrew Gray, high performance manager at Wests Tigers and one of the judges for the event, said while basic calculations about taking the two had been available for some time, considering elements like recent metres gained could help coaches make better "gut feel" calls.

"If one team has ascendancy considerably over the other team, then they probably have a high chance of getting the six and they probably shouldn't take the two," he says.

"They're the 'gut feel' considerations that are going on with coaches in coaches' boxes under a lot of stress and a lot of pressure which is why that could potentially be a really interesting innovation."

Inside Sydney's Olympic Stadium back in October, as the clock ticked past 49 minutes, Ricky Stuart was in just that position.

Against a 12-man defence on the ropes, Mr Cleaves suggests "rugby league intuition" might lead Raiders supporters to believe their team should have gone for it.

However, his model suggests otherwise.

"The Raiders were right to take the two — the model gives them a less than one-in-four chance of scoring a try, but an over 99 per cent chance that Jarrod Croker kicks the goal," he says.

After an off-season of reflection, Raiders fans are entitled to wonder: less than one-in-four … or almost one-in-four.