Many factors influence health and are influenced by it. What does this mean for how we decide which interventions to invest in? In an editorial this week (doi:10.1136/bmj.a1204), Michael Drummond and colleagues say we must do what the textbooks tell us: consider all costs and benefits, no matter whether it’s the health service or other sectors that pick up the bill.

The National Institute for Health and Clinical Excellence gives “mixed messages” on this at the moment, says the editorial. When it appraises drugs and procedures, NICE takes the narrow health service view. When it appraises public health interventions it …