Social desirability bias goes to the core of what makes the jobs of political analysts and professional pollsters difficult. It captures the unhelpful human tendency to say one thing, but do another, often in direct opposition to what we say, because we want to be perceived as “socially desirable”—likable to others or feel good about ourselves.

Former President Donald Trump will hit the campaign trail in Western states as his opponent, Vice President Kamala Harris fixes her attention on the battleground state of Pennsylvania in the East