Colorectal cancer is a leading cause of mortality in developed countries,1 2 yet uptake of screening for this cancer is lower than for other mass cancer screening interventions.3 Globally only about half of the eligible population undergoes colorectal cancer screening after prompts such as mail or telephone invitations, doctors’ recommendations during visits, and mass media campaigns.4 5 Thus, finding effective, feasible ways to motivate the other half of the population to undergo screening is an important priority for public health worldwide. The study by Hoff and colleagues (doi:10.1136/bmj.a2794) looked at one promising approach.6

The authors used data from 12 960 people in the Norwegian Colorectal Cancer Prevention Trial 1 to investigate associations between the uptake of screening (flexible sigmoidoscopy alone or combined with faecal occult blood testing) and the timing of mailed invitations to screening appointments scheduled for six to seven weeks after the date of mailing.6 They found that uptake of screening was higher when …