One of the surprising aspects of this year has been the astonishing lack of performance from Williams and McLaren - and, at the beginning of the season, Force India.
People often wonder how, with the incredible array of technology available to the teams, performance drop-offs like this are possible. They're not just confined to the lesser-funded teams; in 2015 Red Bull produced a car that didn't begin to show the team's normal potential until mid-season.
So what can be the reason? The first thing to remember is that a Formula 1 car needs to be thought of in system engineering terms.