Improving public health information: a data quality intervention in KwaZulu-Natal, South Africa

objective: to evaluate the effect of an intervention to improve the quality of data used to monitor the prevention of mother-to-child transmission (pmtct) of the human immunodeficiency virus in south africa. methods: the study involved 58 antenatal clinics and 20 delivery wards (37 urban, 21 rural and 20 semi-urban) in kwazulu-natal province that provided pmtct services and reported data to the district health information system. the data improvement intervention, which was implemented between may 2008 and march 2009, involved training on data collection and feedback for health information personnel and programme managers, monthly data reviews and data audits at health-care facilities. data on six data elements used to monitor pmtct services and recorded in the information system were compared with source data from health facility registers before, during and after the intervention. data completeness (i.e. their presence in the system) and accuracy (i.e. being within 10% of their true value) were evaluated. findings: the level of data completeness increased from 26% before to 64% after the intervention. similarly, the proportion of data in the information system considered accurate increased from 37% to 65% (p < 0.0001). moreover, the correlation between data in the information system and those from facility registers rose from 0.54 to 0.92. conclusion: a simple, practical data improvement intervention significantly increased the completeness and accuracy of the data used to monitor pmtct services in south africa.