Open Access Research article

Diffusion of subsidized ACTs in accredited drug shops in Tanzania: determinants of stocking and characteristics of early and late adopters

Peter S Larson12*, Prashant Yadav234, Sarah Alphs2, Jean Arkedis5, Julius Massaga6, Oliver Sabot7 and Jessica L Cohen8

Author Affiliations

1 Department of Epidemiology, School of Public Health, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109-2029, USA

2 The William Davidson Institute, University of Michigan, 724 E University Avenue, Ann Arbor, MI 48109, USA

3 Ross School of Business, University of Michigan, 701 Tappan Avenue, Ann Arbor, MI 48109, USA

4 School of Public Health, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109, USA

5 Results for Development Institute, 1100 15th Street, NW, Suite 400, Washington, DC, USA

6 National Institute for Medical Research, P.O. Box 9653, Dar es Salaam, Tanzania

7 Clinton Health Access Initiative, 383 Dorchester Avenue, Suite 400, Boston, MA 02127, USA

8 Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA

For all author emails, please log on.

BMC Health Services Research 2013, 13:526  doi:10.1186/1472-6963-13-526

Published: 18 December 2013



Many households in sub-Saharan Africa utilize the private sector as a primary source of treatment for malaria episodes. Expanding access to effective treatment in private drug shops may help reduce incidence of severe disease and mortality. This research leveraged a longitudinal survey of stocking of subsidized artemisinin combination therapies (ACTs), an effective anti-malarial, in Accredited Drug Dispensing Outlets (ADDOs) in two regions of Tanzania. This provided a unique opportunity to explore shop and market level determinants of product diffusion in a developing country retail market.


356 ADDOs in the Rukwa and Mtwara regions of Tanzania were surveyed at seven points between Feb 2011 and May 2012. Shop level audits were used to measure the availability of subsidized ACTs at each shop. Data on market and shop level factors were collected during the survey and also extracted from GIS layers. Regression and network based methodologies were used. Shops classified as early and late adopters, following Rogers’ model of product diffusion, were compared. The Bass model of product diffusion was applied to determine whether shops stocked ACTs out of a need to imitate market competitors or a desire to satisfy customer needs.


Following the introduction of a subsidy for ACTs, stocking increased from 12% to nearly 80% over the seven survey rounds. Stocking was influenced by higher numbers of proximal shops and clinics, larger customer traffic and the presence of a licensed pharmacist. Early adopters were characterized by a larger percentage of customers seeking care for malaria, a larger catchment and sourcing from specific wholesalers/suppliers. The Bass model of product diffusion indicated that shops were adopting products in response to competitor behavior, rather than customer demand.


Decisions to stock new pharmaceutical products in Tanzanian ADDOs are influenced by a combination of factors related to both market competition and customer demand, but are particularly influenced by the behavior of competing shops. Efforts to expand access to new pharmaceutical products in developing country markets could benefit from initial targeting of high profile shops in competitive markets and wholesale suppliers to encourage faster product diffusion across all drug retailers.

Malaria; ACT; Drug shops; Tanzania; Marketing; Product diffusion