Validity and reliability of data collected by community health workers in rural and peri-urban contexts in Kenya.

Background: Reliability and validity of measurements are important for the interpretation and generalisation of research findings. Valid, reliable and comparable measures of health status of individuals are critical components of the evidence base for health policy. The need for sound information is especially urgent in the case of emerging diseases and other acute health threats, where rapid awareness, investigation and response can save lives and prevent broader national outbreaks and even global pandemics.

Methods: Ten percent of all households visited by CHWs for data collection in different sites (rural and peri-urban) were systematically selected and visited a second time by technically trained research team members. The test-retest method was applied to establish reliability. The Kappa score was used to measure reliability, while sensitivity, specificity, and positive predictive values were used to measure validity.

Results: Inter-observer agreement between the two sets of data in both sites was good; most indicators measured slight agreement. However, some indicators demonstrated greater discrepancies between the two data sets (e.g. measles immunization). Specificity measures were more stable in Butere (rural), which had more than 90% in all the indicators tested, compared to Nyalenda (peri-urban), which fluctuated between 50% and 90%. There were variable reliability results in the peri-urban site for the indicators measured, while the rural site presented more stable results. This is also depicted in the validity measures in both sites.

Conclusions: The paper concludes that there are convincing results that CHWs can accurately and reliably collect certain types of community data which has cost-saving implications, especially for resource poor settings.