Simon Kuper has said that the way to make good decisions is to listen to the wisdom of crowds. One needs to canvas a wide variety of opinion.
The opinion of the crowd appears to be that one shouldn't bring in Mathieu Flamini in games like this. Or in any game, according to some of the more hardline commentators.
Arsenal went down 2-0, in the end, tonight and particular scorn was reserved for Flamini's cameo. He came on as an 82nd sub and was culpable in the concession of an 83rd penalty.
Needless to say, almost all of the hostile tweets wondering why you would bring on Flamini in a game like this were sent after the penalty had been conceded, though some trumpeted their earlier clairvoyance.
He has become the whipping boy for tonight's loss. Despite the fact that he came on with the score already at 1-0. He is currently trending in Ireland. Here's a flavour.
Flamini won a prize with the Make A Wish Foundation to play for Arsenal. It's the only explanation
— James Mullaney (@mullaneyjames) February 23, 2016
Just a reminder, Flamini gets paid to do this.
— Mahmoud Jaber (@MahmuudJaber) February 23, 2016
Flamini should not even be at the club imo.. That's what happens when you hoard the money
— Andy Stewart (@redofpurple) February 23, 2016
You know it's funny cause when Flamini came on I instantly thought "Imagine bringing on Flamini in a match like this." ?
— MR99 (@MoTheArabKeeper) February 23, 2016
Flamini has too much money to be spending to have time for a Champions League quarter final... Another good business decision from him
— Andy (@AJ3) February 23, 2016
Flamini is a good player as long as he doesn't pass, shoot, header or tackle #Baller
— Josh Jones (@j91jjj) February 23, 2016
Don't blame Flamini. Blame the person who keeps playing him, surely..
— Big Grant (@Dilligaf59) February 23, 2016
Flamini the the lumberjack comes on and totally destroys any chance of getting any sort of result at the nou camp
— Maraldo (@Gunner_D7) February 23, 2016
But some offered a contrary view, focusing instead on Per Mertesacker's wooden touch which put Flamini in bother.
Giroud, Sanchez especially poor. Per at fault for 2nd. Ramsey kept giving the ball away. But yes lets all dig out Flamini
— Darren (@DarrenArsenal1) February 23, 2016
Flamini will get the stick for the pen but mertesacker is to blame. That was a horrendous touch that fell straight to Messi's feet.
— Sandy (@Buchanamania) February 23, 2016