Using multiple sources to improve and measure case ascertainment in surveillance studies: 20 years of the British Paediatric Surveillance Unit

Abstract

Active surveillance through the BPSU remains a timely and reliable primary source of cases, but employing additional reporting sources is effective in enhancing case ascertainment. When the assumptions for its valid use are met, capture-recapture analysis allows the estimation of completeness of ascertainment. It is essential to define the purpose of an additional source at the outset of a study and to ensure that subsequent analysis is appropriate.