Evidence of impact

The quality and size of the evidence base for the impact of mass media on health behaviours has been limited by the quality of evaluation designs in many cases. In particular:

  • Evaluations are often limited to indicators focusing on reported or intended, rather than observed, behaviour
  • Many evaluations collect data on trends in health behaviours, but few have looked at impact on health outcomes

As a result, it is often difficult to attribute behaviour change outcomes to a mass media campaign. Nonetheless, a 2001 Cochrane review concluded that “despite the limited information about key aspects of mass media interventions and the poor quality of available primary research, there is evidence that these channels of communication may have an important role in influencing the use of health care interventions.”

Campaigns run by DMI staff have used progressively more robust evaluation designs to measure impact, as detailed below. The most robust evaluation of all is our randomised controlled trial in Burkina Faso.

We have a track record in developing countries in Africa, Asia and Latin America. Many of our campaigns have demonstrated dramatic increases in the uptake of many basic interventions. Others have changed behaviours at the household level, directly improving health outcomes.

We also have evidence of a ‘dose-response’ relationship, showing that people with higher exposure to the campaign exhibit higher rates of the targeted behaviours. This helps us to attribute impact to the campaigns themselves, rather than to other factors. Two examples (from a maternal and child mortality campaign run by our team in Cambodia in 2006) are given below. They show the percentage of parents reporting washing their children’s hands to prevent diarrhoea, and the percentage of women reporting attendance of ante-natal check-ups.