This document summarizes a re-review of a systematic review on the impacts of water, sanitation, and hygiene (WASH) interventions on diarrhea. The re-review found that in over 45% of studies, impacts were more complex than just diarrhea reduction. Many interventions unintentionally impacted other health and development factors like nutrition, education, and gender relations. It also found that in over 50% of studies, individual and community actions influenced the benefits and harms experienced from the interventions in ways not considered. The re-review calls for WASH interventions and evaluations to better account for these complexities and interactions to maximize impacts.

1. Multiple benefits and harms in water,
sanitation and hygiene interventions:
A re-review of a systematic review
Michael Loevinsohn1, Lyla Mehta1, Katie Cuming2, Alan Nicol1,
Oliver Cumming3 and Jeroen Ensink3
19 September 2012, Woburn House, Tavistock Square
1
IDS; 2 DFID; 3 LSHTM

2. Water, sanitation and hygiene
• Critical to wellbeing yet large gaps in coverage
persist
• Designs still often fail to meet needs in health
and other domains
• “Health” and “development” disciplinary/
practice communities remain disconnected
 H0 : Important gains possible from bridging this
divide

3. Re-review of Waddington et al 2009
Systematic review: WASH impact on diarrhoea
• Realist review of all evidence, including info not
analysed by article and/or SR authors
• Theory-based
– public health: understandings of key mechanisms
– development: understandings of individual and
collective agency (esp. common property, gender,
sustainable livelihood theory)
• Excluded study designs with little context
• 1 health, 1 development researcher reviewed each
article, then deliberated on 4 questions

4. Deliberation outcomes:
“Likely” or “More than possible” N=22
• Is the intervention substantially more complex
than considered by Waddington et al? 18.2%
• Are impacts substantially understated if only
diarrhoea outcome is considered? 45.5%
• Are actions by individuals, households or
communities substantially influencing the
benefits and harms experienced? 50.0%
• Would these other impacts substantially affect
the level, distribution or sustainability of the
diarrhoea morbidity outcome? 45.5 %

5. Is the intervention substantially more
complex than considered by Waddington?
• Kolahi et al 2009: sanitation in Tehran
– Large improvement in maternal education in treated but
not control neighbourhoods (analysis of background data)
– Suggests an independent intervention
– Better maternal care may have contributed to reduced
diarrhoea, complicating attribution
• Moraes et al 2003: sanitation in Salvador
– Beyond sewers, treated got land title, better water supply
– More water may have contributed to reduced diarrhoea
– Better off areas were treated, visibly exacerbating
inequalities

6. Are impacts substantially understated if
only diarrhoea outcome is considered?
• Aziz et al 1990: water supply, sanitation - Bangladesh
– Women use pumps to irrigate kitchen gardens
– Better nutrition may contribute to reduced diarrhoea
– Women prize “improved QoL”; may also increase
commitment to maintain system, enhancing sustainability
• Ahmed et al 2003: hygiene - Bangladesh
– Field workers discourage bottle-feeding due to diarrhoea
risk but reduced milk intake increases stunting
– Stunting known to increase diarrhoea mortality, other
developmental effects.
– Intervention’s impact more than possibly reduced

7. Are individual, household or community
actions influencing benefits and harms?
• Kremer et al 2009: water supply - Kenya
– Control HHs use improved springs in treated area
– Diarrhoea reduced in control areas, diminishes apparent
effect of intervention
• “Contamination” evident in 3 other articles
– Control people getting hold of or treated people actively
spreading the intervention
– Considered mostly as an estimation problem
– Little thought given to harnessing these efforts to enhance
impact and sustainability

8. Implications for health and development
• Design and implementation of WASH interventions
– Plan for, incorporate agency
– Enhance capacity to manage multiple benefits and harms
• Evaluation methods and practice
– More realistic designs e.g. incorporating spread
– More attention to processes and context
• Systematic reviews and the knowledge economy
– Create demand for evaluation of innovative designs
– Commission SRs focused not on mean effects but e.g.
conditions under which exceptional results are realized