Effect sizes differ across topics.
According to Snyder,
The average health campaign affects the intervention community by about 5 percentage points.
Average health campaign, r = .05
International breastfeeding campaigns, r = .18
Seatbelt campaigns, r = .15
Dental care campaigns, r = .13
In-school nutrition campaigns for youth, r = .12
Adult alcohol reduction, r = .11
Fruit and vegetable media campaigns, r = .08
Heart disease prevention, r = .05
Sexual risk taking, r = .04
Mammography screening, r = .04
Adult smoking prevention, r = .04
Tobacco prevention, r =.04
Average family planning campaign, r = .06
- Effects on knowledge, r = .11
- Effects on attitudes, r = .07
- Effects on communicating with spouse, r = .05
Average youth smoking campaign, r = .06
Average youth alcohol and smoking prevention, r = .04-.07
Average youth drug and marijuana campaign, r = .01-.02
- Effects on knowledge, r = -.01-.01
- Effects on attitudes, r = .03
DMI claims that it can lower child mortality rates in "most low-income countries" by 16-23%. Given that (1) DMI's campaigns are aimed at populations where health issues are rampant and (2) that they tend to play their messages repeatedly over a long-term time span, I think that number is at least realistic. I don't know of any other behaviour change communication campaign claiming to have such a high impact, however.
DMI offers more data on their effectiveness:
- A behaviour change radio campaign can save 74,500 under-five lives and 2,500 maternal lives every year.
- This assumes that we can reach 16 million radio listeners over the age of 15 on a regular basis.
- We can predict impact by disease (e.g. for under-fives: 26% diarrhea, 23% pneumonia, 23% malaria, 26% neonatal).
- We can predict impact by behaviour (e.g. exclusive breastfeeding up from 16% to 29%, saving 6,400 lives per year.)
- We can predict the cost-effectiveness of our campaigns (a nationwide campaign in DRC would cost $2 per DALY).
DMI provides a lot of facts about their media interventions but they don't publicly demonstrate all the steps leading toward these figures. I would like to see something like:
"X people have malaria each year. Y% of people with malaria die from it per year. If our malaria interventions are aired with A frequency for B months, we can increase the amount of malaria survivors by C%, saving Z lives. This campaign would cost D dollars and would thus cost $2 per DALY."
It's difficult to take a charity at their word if we aren't provided with the concrete evidence.
If the average health campaign boosts effectiveness by 5%, is that good enough? Is it worth the trouble of a media campaign if it's only going to increase conversions from 13% to 18%? If we're talking about life and death issues, and production costs are reasonable, then it's pretty clear to me that the campaigns are worth it. The 5% conversion boost might not be strong enough to make health communication the optimal health intervention, however, especially if the behaviour change it's targeting is of relatively low importance. If DMI's ~20% child mortality reduction figures are accurate, then their media interventions should clearly be high priority health interventions.