ABSTRACT: Many family health innovations that have been shown to be both efficacious and cost-effective fail to scale up for widespread use particularly in low-income and middle-income countries (LMIC). Although individual cases of successful scale-up, in which widespread take up occurs, have been described, we lack an integrated and practical model of scale-up that may be applicable to a wide range of public health innovations in LMIC.To develop an integrated and practical model of scale-up that synthesises experiences of family health programmes in LMICs.We conducted a mixed methods study that included in-depth interviews with 33 key informants and a systematic review of peer-reviewed and grey literature from 11 electronic databases and 20 global health agency web sites.We included key informants and studies that reported on the scale up of several family health innovations including Depo-Provera as an example of a product innovation, exclusive breastfeeding as an example of a health behaviour innovation, community health workers (CHWs) as an example of an organisational innovation and social marketing as an example of a business model innovation. Key informants were drawn from non-governmental, government and international organisations using snowball sampling. An article was excluded if the article: did not meet the study's definition of the innovation; did not address dissemination, diffusion, scale up or sustainability of the innovation; did not address low-income or middle-income countries; was superficial in its discussion and/or did not provide empirical evidence about scale-up of the innovation; was not available online in full text; or was not available in English, French, Spanish or Portuguese, resulting in a final sample of 41 peer-reviewed articles and 30 grey literature sources.We used the constant comparative method of qualitative data analysis to extract recurrent themes from the interviews, and we integrated these themes with findings from the literature review to generate the proposed model of scale-up. For the systematic review, screening was conducted independently by two team members to ensure consistent application of the predetermined exclusion criteria. Data extraction from the final sample of peer-reviewed and grey literature was conducted independently by two team members using a pre-established data extraction form to list the enabling factors and barriers to dissemination, diffusion, scale up and sustainability.The resulting model-the AIDED model-includes five non-linear, interrelated components: (1) assess the landscape, (2) innovate to fit user receptivity, (3) develop support, (4) engage user groups and (5) devolve efforts for spreading innovation. Our findings suggest that successful scale-up occurs within a complex adaptive system, characterised by interdependent parts, multiple feedback loops and several potential paths to achieve intended outcomes. Failure to scale up may be attributable to insufficient assessment of user groups in context, lack of fit of the innovation with user receptivity, inability to address resistance from stakeholders and inadequate engagement with user groups.The inductive approach used to construct the AIDED model did not allow for simultaneous empirical testing of the model. Furthermore, the literature may have publication bias in which negative studies are under-represented, although we did find examples of unsuccessful scale-up. Last, the AIDED model did not address long-term, sustained use of innovations that are successfully scaled up, which would require longer-term follow-up than is common in the literature.Flexible strategies of assessment, innovation, development, engagement and devolution are required to enable effective change in the use of family health innovations in LMIC.
