Fig 3. Efficiency frontier of population QALYs vs. population costs in the 2014 population of migrants under post-landing surveillance.

The frontier is read from left to right, with interventions connected if they fall on the frontier. Interventions subsequent to the initial intervention have an increased cost, but an increased benefit, and represent the next best value at increasing funding thresholds. The slope between two connected interventions represents cost-effectiveness: a steeper slope represents poorer cost-effectiveness between interventions, while a shallow slope represents better cost-effectiveness. QALY: quality adjusted life year; SEQ: sequential screening; TST: tuberculin skin test; IGRA: interferon-gamma release assay; INH: isoniazid; RIF: rifampin.