Water and sanitation interventions for better child health: Evidence from a synthetic review Hugh Waddington Birte Snilstveit Howard White Lorna Fewtrell 3ie

2 Contents n Objectives n Methodology n Results: effectiveness n Results: sustainability n Conclusions

3 1. Objectives of the synthetic review Conduct review to Cochrane/Campbell standards Mixed methods: analysis of quantitative and qualitative information Synthesise quantitative information using meta-analysis: assess whether existing ‘consensus’ stands up to inclusion of new studies, and internal and external validity criteria Theory-based: draw out behavioural and contextual factors shaping success/failure and (likely) sustainability

4 2. Methodology Extensive search (published and unpublished sources) Inclusion criteria: impact of WSH on diarrhoea; experimental and quasi- experimental methods Coding of studies:  Internal validity: study design; data quality  External validity: contextual information  Quantitative and qualitative information relating to process, context, behaviour, confounding, moderation Effectiveness of interventions assessed using:  Meta-analysis (fixed/random effects models; impact heterogeneity, publication bias)  Meta-regression Sustainability of interventions assessed using quantitative and qualitative information relating to process (outputs), study length and size, replicability

5 84 studies included in meta-analysis 21 studies from the searches met the inclusion criteria 63 studies from previous reviews met the inclusion criteria Review against inclusion criteria Abstract review of 278 papers, of which full text copies were obtained of 68 Full text copies were obtained of all 110 studies from previous reviews Search strategy Title review of 19,233 papers identified from searches of databases, organisations and communication with researchers 110 studies identified from bibliographies of previous reviews

6 3. Results: about the interventions Total num Num RCTs Total sample Ave sample Ave length (months) Water supply 14064,6515,87719 Water treatment402716, Point of use water treatment (POU) , Source water treatment524, Sanitation13233,6823,36816 Hygiene381429,2541,08312 Hand-washing with soap9412,4721,3866 Education291016,

7 Effectiveness: Water supply interventions

8 Effectiveness: Water treatment interventions

9 Effectiveness: Sanitation interventions

10 Effectiveness: Hygiene interventions

11 Heterogeneity – ‘high quality’

12 A closer look at water treatment Effect95% CINum studies Point of use Source No placebo/blinding Placebo/blinded trials Placebo/blinded trials excl. Luby et al. (2004, 2006) Possible conflict of interest No conflict of interest declared

13 4. Sustainability Water supply and sanitation: sustainability/scalability assessed Water treatment and hygiene: replicability demonstrated; sustainability and scalability not => only 5 follow-up studies assessing compliance + health impact over one year after intervention completed Most studies assess adoption/compliance with intervention => success / failure  Contextual factors identified, often through use of moderator (interaction variable) in analysis: e.g. age, carer’s education level, income, time.  Behavioural factors identified: individual preferences (e.g. taste) and agency (intra-household effects), intra-community ownership + interpersonal networks

14 Sustainability: quantitative

15 Sustainability: qualitative (water treatment) 3 follow-up studies of successful trials were conducted over one year after the initial intervention ended:  Brown et al (2007): ceramic filter provision in Cambodia; 3 years later only 31% compliance  Iijima et al (2001): pasteurisation in Kenya; 4 years later only 30% compliance  Luby et al (2008): water disinfectant in Guatemala; compliance (repeated use) only 5%. One study evaluated the reasons for low compliance of unsuccessful intervention: source water treatment (UV filtration) in rural Mexico (de Wilde et al 2008):  Community capacity to manage, physical faults or under-valuing of safe water by users were NOT found to be limiting the intervention’s effectiveness  Constraints (money & time) and availability of other sources, meant households chose more convenient water sources

16 No one single intervention for improving global access to water and sanitation for reducing diarrhoeal disease:  the ‘right’ solution is the one that fits the (social, economic, political) context  emphasise behavioural factors, particularly where these are of overriding importance to adoption (water quality + hygiene interventions) 5. Conclusions

17 5. Conclusions (cont’d) Effectiveness:  Water supply interventions least effective, excl household connection  Water treatment at point-of-use very effective, but concerns about study quality (blinding) and conflict of interest  Water treatment at source less effective but few high quality studies  Sanitation effective – more studies needed  Hygiene interventions are effective (at least in short term) but resource intensive  Interventions substitutes (results not reported) Evidence on sustainability + scalability of water treatment and hygiene interventions limited