My main interest is in design and evaluation of diagnostic impact interventions, with my work contributing to LSHTM Research Excellence Framework case studies in 2014 (TB screening in people living with HIV) and 2021 (Making HIV self-testing available to millions as a diagnostic strategy for low and middle income countries). My cluster-randomised trial of active case-finding for TB (Corbett Lancet 2010: DETECTB trial) triggered international policy change with a Rapid Policy Update in 2011 and subsequent Guideline Development Group by World Health Organization (WHO) with updated Guidelines on Systematic Screening for Active TB Disease released in 2013 and 2021, providing the first updates since the 1970s. My work on HIV self-testing was recognized as fundamental in 3 WHO/UNAIDS Rapid Technical Updates (2011-14) and substantive Guidelines (2016, 2019). My work with Rashida Ferrand influenced adolescent HIV WHO Guidelines in 2012 and 2015.