Speaking in an exclusive interview with AUTOSPORT, team principal Martin Whitmarsh said that the combination of the 2012 car over-performing compared to its wind tunnel model and the 2013 car underperforming led to McLaren losing its way at the start of this year.
"Sometimes you're lucky in life and you stick all the elements together and they add up," said Whitmarsh. "Sometimes they just don't.
"There were times when it's come good and we don't really know why.
"At the end of last year, some of the developments over-performed. We were actually over-delivering at the track.
"That was another thing that caused this: we're always looking at the correlation between full-scale wind tunnel and CFD, and there's always an offset between those, and we work on that.
"That was another thing that has exacerbated this situation. The real  car was actually better than the wind tunnel [model]."