Strategy has always been about defying averages — doing something exceptional that earns a company correspondingly exceptional rewards in the market. Today, that is still true, but the relentless churn and volatility in the business environment mean that simply outperforming the average is not enough. Rather, the true test of leadership is continuing to outperform over time.

We recently studied the performance trajectories of 22,000 companies over the last four decades. The results show that across a wide range of metrics, strong performance has become far less sustainable than in the past. Companies that manage to beat the average for their industry must now struggle much harder to maintain their leading position.

Of the companies that significantly outperformed their sector average, our analysis found that just 17% were also able to maintain that performance advantage over the following five years. These companies — including organizations like Apple and Alphabet — continually find new sources of competitive advantage by reinventing their businesses and adapting to evolving market conditions. Their example offers lessons for leadership teams trying to fight the relentless pull to the mean.