The Economics of Social Marketing: The Case of Mosquito Nets in Tanzania

Published in the Social Science & Medicine journal, this article offers an economic analysis of a social marketing project for insecticide-treated mosquito nets distribution in Tanzania. The main focal point is the ways in which social marketing can stimulate demand for nets - a public sector input, and encourage the growth of product supplies - a private sector output with public health impact. Instead of focusing on the cost-benefit aspect of social marketing, the present study investigates the economics of social marketing, by asking two key questions: (1) how does social marketing affect the market for nets (i.e., price and coverage)?; and (2) what does the added cost of social marketing "buy" in terms of coverage and equity, compared with an unassisted commercial sector model?


Evaluation/Research Methodologies:

The social marketing project, carried out between 1996 and 2000, employed the following communications strategies: advertising on billboards and sales agent bicycles; and promotional events such as video shows. In addition, the project involved sensitisation of community leaders, and a voucher scheme to increase ownership and use among pregnant women and young children.

The primary design of the economic analysis relied on the comparison between an intervention area (Kilombero district) and a matching control area (Kilosa district). At the time of data collection, the social marketing campaign had been operating for three years. The authors tested the following hypothesis: social marketing would increase coverage of mosquito nets by outwardly shifting both supply and demand. The supply and demand data for Kilombero and Kilosa districts were collected from a variety of sources, including: a household survey; a survey of store owners selling nets; residential focus groups; mosquito nets production data from manufactures; and project accounting information.



Key Findings/Impact:
In the intervention area (Kilombero) the proportion of households with at least one net rose from 37% in 1996 to 72% in 1999, comparing positively to the changes in the control area during the same period, from 21% to 28%. Survey responses and focus group findings also indicated that the price of nets had fallen dramatically during the same period. The authors explain these changes from both supply and demand points of view.

With respect to the supply, the national production capacity of mosquito nets as well as the local availability of nets had increased during the late 90s. Factors contributing to the gains included the entrance of new mosquito net producers in the national market, tax elimination for the net producers, and the likely effects of several public and nonprofit malaria control campaigns (including the present Kilombero project). The availability of nets had improved in both the intervention and control areas, but in the control area the net distribution was not very reliable in less populated areas. In the intervention area, at least one net outlet operated in every village.

The social marketing campaign was expected to have even more tangible impacts on demand-side variables, such as net ownership and awareness of insecticide-treated nets. The evidence supported this model. Households in the intervention area were significantly more likely to own a net, and had greater knowledge of insecticide-treated nets. Although there were some variations between the intervention and control areas in terms of their economic characteristics (e.g., household income, cash income sources, household assets, etc.), the authors argue that the greater outward shift in demand in the intervention area was not a simple reflection of the economic gaps between the two areas. In fact, among six variables related to household wealth, only two variables had statistically significant impacts on household net ownership. In the intervention area, three out of four variables specifically related to the social marketing campaign (i.e., knowledge of insecticide-treated nets, knowledge of voucher scheme, use of anti-mosquito products) had positive impacts on net ownership. Dispensaries, population survey interviewers, road side billboards, school songs, T-shirts, advertising on mobile vans and bicycles, posters were the sources of net information commonly cited by the residents in the intervention area. In the control area, the knowledge of insecticide-treated nets was very low among residents, and even when individuals had heard about the product they tended to have very little understanding of why such nets were effective in preventing malaria.



Answering the second research question, the authors found that the cost per net delivered by the social marketing model was more than two times higher than the unassisted commercial sector. However, social marketing was associated with a significantly greater increase in coverage, higher coverage in households with pregnant women and children under 5 years, in the poorest income quartile, and in village peripheries.

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