Mergers routinely fail to deliver expected synergies. Strategic plans frequently ignore competitive responses. And large investment projects are over budget and over time – over and over again. Why is that?

In a recent McKinsey survey of 2,207 executives, only 28 percent said that the quality of strategic decisions in their companies was generally good, 60 percent thought that bad decisions were about as frequent as good ones, and the remaining 12 percent thought good decisions were altogether infrequent.

It is the case that left unchecked, subconscious biases can undermine strategic decision-making. McKinsey is now embarking on a fascinating series on improving strategic decision making, presenting new research that quantifies the financial benefits of mitigating biases.

In the first of the series, they concede that few corporate strategists making important decisions consciously take into account the cognitive biases – systematic tendencies to deviate from rational calculations – revealed by behavioural economics.

It’s easy to see why: unlike in fields such as finance and marketing, where executives can use psychology to make the most of the biases residing in others, in strategic decision making, leaders need to recognise their own biases.