Table 3.

Examples of studies of water, sanitation and hygiene interventions conducted in Bangladesh corresponding to the three categories of research on behaviour-change interventions delivered by community health workers (CHWs)

Type of research	Example of this type of research	Scale, setting and duration of study	CHW to household ratio	System for CHW oversight, training and intervention dissemination
Efficacy research	WASH Benefits Bangladesh study1	Population; ~ 4169 intervention households; Location: 4 rural sub-districts Duration; 2012–2015 (2-year intervention exposure)	1:8 CHWs; N = 540	CHW oversight; Coordinated by study team (Fig. 3) Transparent and rigorous recruitment criteria and methods Identified as employee to maintain morale and prestige in the community Delivery skills formally assessed Accessible supervision, ~ 12 CHWs/supervisor CHWs received study technologies to encourage CHW and recipient self-efficacy Stipend paid using mobile phone network Training: Provided by project staff Refreshers: scheduled and triggered by fidelity measures Included messages on study staff withdrawal and intervention sustainability Dissemination; Based on communication plan and IBM-WASH theoretical model2 Evaluated messages were understood by recipients Community meetings during roll out for acceptability, expectation management, conflict reduction Sequenced technology and BCC component delivery for combined interventions
Effectiveness research	Introduction of cholera vaccine in Bangladesh3	Population; 240,000 Location: urban slums, Dhaka Duration: 2011–2013 (2-year intervention exposure)	1:290 CHWs; N = 55	CHW oversight Single NGO with close project staff involvement, ~ 16 CHWs/supervisor Training Delivered by NGO, developed by project staff Dissemination: NGO-hired CHWs from the local community-delivered interpersonal communications. NGO-delivered hardware
Implementation research	Sanitation, hygiene Education and water supply in Bangladesh Health Impact Study4	Population 20 million Location: 58 rural sub-districts Duration: 2007–2012 (4–5-year intervention exposure)	Up to 1:550 CHWs; N = 10,0005	CHW oversight; multiple NGOs; individual NGOs responsible for hiring and supervision Training: multiple NGOs Dissemination: multiple NGO-hired CHWs from the local community, delivered interpersonal communications

¹Arnold et al. [6], www.washbenefits.net; ²Dreibelbis et al. [21]; ³ICVB; the Introduction of Cholera Vaccine in Bangladesh trial [16]; ⁴SHEWA-B; Sanitation, Hygiene Education and Water supply in Bangladesh Health Impact Study [19]; ⁵A total of ~ 10,000 CHWs were engaged in dissemination, but not necessarily the full 5-year intervention period

NGO non-governmental organization