Background: Handwashing and improved sanitation have been shown to significantly reduce the risk of diarrhoea. Despite this benefit, the intended health impacts of Water, Sanitation and Hygiene (WASH) interventions were generally not attained and the 2015 Millennium Development Goal on sanitation was missed.
Objectives: As part of a Campbell systematic review on the effectiveness of WASH promotion programmes on behaviour change in low- and middle-income countries, we aimed to assess the level of standardisation of WASH behaviour outcomes.
Methods: Via systematic screening of 12 databases/24 websites, studies investigating the effect of WASH promotion programmes on the following behaviour-change outcomes were included: handwashing (at critical times), latrine use, safe faeces disposal and open defecation practices. The level of standardisation was evaluated by the difference in 1) type of data (binary versus continuous data); 2) timing of assessment (uptake (during implementation) versus adherence (within 1 year after end of implementation) versus longer-term use (>1 year after end of implementation); and, 3) study design (experimental versus quasi-experimental/observational studies).
Results: We identified 35 studies (28 experimental studies and 7 quasi-experimental/observational studies) assessing 87 handwashing and 39 sanitation outcomes. When stratifying the outcomes by type of data, timing of assessment and type of study design, it was so diverse that the ability to synthesise outcomes via meta-analyses was rare, complicating proper interpretation of the data. Only handwashing after defecation/before cooking/before eating (Figure 1) and open defecation practices were assessed ≥3 times via a uniform methodology (i.e. collection of binary data during implementation in experimental study designs).
Conclusions: Systematic and uniform definitions and monitoring of standardised WASH behaviour outcomes is needed to improve use of evidence and conduct of evidence synthesis. This would help governments and international bodies to formulate clear and more robust recommendations.