An assessment of the replicability of a standard and modified sanitary risk protocol for groundwater sources in Greater Accra

Abstract

Sanitary risk inspection, the systematic observation of contamination hazards, is often used to manage safety of water sources such as wells and boreholes. However, the replicability of sanitary risk inspections undertaken by different observers has not been studied. This study aimed to assess the replicability of sanitary risk inspections by two different observers in urban and peri-urban neighbourhoods of Greater Accra, Ghana. Two observers independently used a standard protocol to record contamination hazards around 62 groundwater sources, additionally recording urban-specific hazards such as damaged sewage pipes via a modified protocol. We calculated risk scores as the proportion of hazards observed at each source, separately for each observer. Linn’s concordance correlation coefficient indicated very high agreement between the two observers’ risk scores (n = 62; c = 0.949, 95% confidence limits 0.917–0.968). However, risk scores from urban-specific observations were uncorrelated with those from the standard protocol (r = 0.11, p = 0.41 for observer 1; r = 0.16, p = 0.22 for observer 2). Ours is the first study of replicability of sanitary risk observations and suggests high inter-observer agreement. However, urban contamination hazards were not captured using the standard protocol. In the future, assessment of inter-observer agreement and observations of urban-specific hazards could be incorporated into nationwide or regional sanitary risk surveys.

An Assessment of Inter-Observer Agreement in Water Source Classification and Sanitary Risk Observations

“…Our findings from rural Kenya indicate much lower agreement between observers recording contamination hazards than we identified in our earlier study in Greater Accra, Ghana (Yentumi et al 2018). There are several reasons why this might be the case.…”

“…If sanitary risk inspection protocols are to form a robust basis for water source remediation or comparing the relative safety of sources in different areas via water source surveys, then observations need to be consistent across observers. We recently conducted a small-scale study of inter-observer agreement of sanitary risk observations at groundwater sources in Greater Accra, Ghana, finding high agreement between two observers (Yentumi et al 2018). To avoid personal safety risks from lone working, both observers visited water sources in Greater Accra at the same time, though they observed and recorded hazards separately.…”

“…A subsidiary objective is to quantify uncertainty in the classification of water source types. In doing so, we seek to build on our earlier study (Yentumi et al 2018), addressing some of its limitations and expanding the study design to include observations by more than two observers and other rural water source types, notably rainwater harvesting systems. As a second subsidiary objective, we also seek to assess the robustness of observational evidence for contact between water sources and livestock and thereby the implications for diarrhoeal disease control.…”

“…To estimate the minimum required sample size for our study, we used the published method for approximating the variance of the estimated limits of agreement (Bland and Altman 1999), and the standard deviation of differences between percentage sanitary risk scores recorded by two observers of wells and boreholes in Greater Accra, Ghana (Yentumi et al 2018). We estimated that observations of at least 92 water sources would give 95% confidence limits of 19.91% for the limits of agreement.…”

Does Training Improve Sanitary Inspection Answer Agreement between Inspectors? Quantitative Evidence from the Mukono District, Uganda

“…Studies of risk perception within industries such as aviation [24][25][26] have shown diverse trends in risk perception between experts, professionals and novices. Though the importance of both capacity building within the wider water sector [27] and, more specifically, suitable training prior to undertaking an SI is acknowledged in the literature [6,28], there is limited published data regarding the consistency of SI inter-inspector answer agreement [29,30]. However, such consistency is vital to allow for potential comparability of SI outputs.…”