The weekend effect—how strong is the evidence?

The health secretary, Jeremy Hunt, has cited various evidence to support the government’s push to improve hospital services on Saturdays and Sundays and to justify imposing new contracts on junior doctors.1 2 3 4 5 6 But as the junior doctors strike has rolled on, studies on the so called weekend effect—excess deaths in people admitted to hospital at weekends—have become political footballs used by all parties to justify their positions, leading to confusion about what the evidence really shows.

Of the 15 substantive studies dominating public debate (the 11 Hunt refers to and four new papers, including one published in The BMJ this week), none has reached definitive conclusions about the cause of the weekend effect , and two recent studies have even questioned whether there is a weekend effect at all. No study has specifically looked at whether the numbers of junior doctors on duty at weekends affects outcomes. Those that have looked at senior doctor staffing have reached mixed conclusions. And there are many potential contributing factors that have so far received little attention.

So should policy makers wait for more comprehensive evidence? Or is it obvious what needs to be done? Is there a risk that the government pushes on with its plan for enhanced seven day services only to find the weekend effect remains?