“We have to follow the data, this is how the sport works,” said Mercedes team boss Toto Wolff after a strategic blunder lost Lewis Hamilton the Monaco Grand Prix. On the surface, it seems an odd position to take. But it’s rather more complex than that.

Although many viewers were reportedly screaming at their TVs when Mercedes chose to bring Hamilton in for that late safety car pit stop which lost him the race, so ‘obvious’ was the error, they may not have been had they been armed with the same data as the team. And in F1 data is king. Many have said had Ross Brawn still been in charge, he’d have not made that call – and quite possibly he wouldn’t have. But consider what Ross himself said in an interview I did with him last year: “In the early years of the refuelling era we [Ferrari] relied much more on intuition than our main rivals McLaren who were much more data-driven, and I’d say our calls were better than theirs about 60% of the time. But as it became more of a science and they began to have whole teams of people crunching numbers back at base, it gave them a wider view of all the possibilities – and they became better than us. We had to respond and ramp up our own strategic data analysis.”

Relying only on the data will sometimes cause you to miss the obvious. But if the data-driven approach gives better outcomes in the long run, then it’s not unnatural for a team to commit fully to that philosophy. And if you’re doing that, how do you know in real time when this is one of those times to ignore the data?

Mercedes messed up big time, of that there can be no doubt. But the error only looked obvious when applying just an intuitive common sense approach. On this occasion that common sense view would have kept Hamilton on course for victory regardless of what Ferrari did with Sebastian Vettel. We can see this 100% in hindsight. For those that say they could see it 100% at the time, that was only because they did not have the same depth of data regarding possible outcomes. Nonsense you say? Consider the following, then put yourself in the position of the guy whose call it was.

Sometimes the obvious is less so when you scratch beneath the surface. Reality is often multi-faceted. There were in fact several ways it could have played out – and that largely depended upon an unknown: how long Hamilton’s used prime tyres would take to reach working temperature after they had cooled behind the safety car. It turned out not to be an issue – but it might have done. If the tyres had behaved anything like they had the day before – when even new primes needed five laps to reach temperature – it was feasible that a set of used primes would never have regained their temperature. This is a phenomenon we’ve seen many times before; with so little rubber left on the tread, it often cannot bend and twist enough to generate the heat needed to initiate the chemical bonding process that’s one of the two mechanisms of a tyre’s grip. Without being able to generate good cornering loads, the core of the tyre remains brittle and inflexible too and cannot help the tread by bending under load, thereby making it yet more difficult for the tread etc in a vicious downwards spiral. It was quite feasible that such a tyre would have been disastrously gripless once the race restarted – possibly to the tune of five/six seconds per lap.

Even around Monaco, 6s per lap would be enough to get you overtaken on-track against a grippy new option-tyred Ferrari in the remaining eight laps. It would have vastly more traction out of Portier, would get a run going through the tunnel and would then be able to brake much later for the chicane – job done. It didn’t happen like that of course – as it turned out there was plenty of tread left on Hamilton’s old tyres and the hotter track temperatures of Sunday meant warm-up wasn’t anything like the issue it had been on Saturday. But it might have; there was no way of knowing in advance if the higher track temperature was enough to cancel that risk.

The data-driven approach that the team relied upon was inappropriate for the moment, but to compound that was the fact that a crucial number in the calculation – how long it would take Hamilton to arrive in the pits - was wrong by two seconds. Normally GPS data would never have allowed such an error, as the speed is relayed to the team in real time. But on this occasion, with GPS reception notoriously poor at Monaco because of the surrounding mountains and density of the buildings, it cannot be relied upon. They were instead taking their speed information from the timing loops that are all around the circuit, from beams placed every couple of hundred metres or so. These can only give an update of the car’s position every time it passes a beam. Based on that, it looked to the team that Hamilton would arrive in the pits with enough time to change tyres and emerge still in the lead. They could thereby cover off the possibility of his tyres not coming up to temperature, Ferrari pitting Vettel for new super-softs and picking the Mercs off. There seemed to be no downside. So why not do it?

There was disagreement within the camp about what to do, and lots of confusing discussion in a time-pressured situation. Hamilton himself fed into this pressure. As he drove up the old pit straight he saw on the big spectator screens the Mercedes crew standing in the pitlane. He assumed this was for Rosberg. This belief was reinforced by the fact that he still couldn’t see Rosberg in his mirrors (because he was so far behind). He was concerned that Rosberg might therefore be able to come at him on fresh tyres while he floundered on old, cold rubber. So he relayed his concern about how gripless his tyres now were and whether they’d be in any shape to compete upon the restart. The team didn’t realise he thought Rosberg had pitted. To them, Hamilton’s concern gave support to those following the data.

Tyre warm up, wrong data, incorrect unvoiced assumptions from Hamilton, a team that operates on data is king philosophy (because overall, in the long run, that’s proven to work best). Given all those pieces of information, with a decision required right now, would you still take the intuitive approach? Maybe you would. But it was not as black and white as it looked from the outside.

MH