1) An operations research (OR) technique is used
↑ or ↓	□ Simulation model (e.g. discrete event, agent-based, etc.) □ Optimisation model (e.g. linear and non-linear programming, goal programming, location-allocation models) □ Decision analysis, decision tree models □ Stochastic, compartmental, state transition models (e.g. Markov) □ General mathematical or probabilistic models of disease progression and/or transmission will be considered if Criteria 2 is met
and
2) An OR problem is exploreda
↑ or ↓	□ Several competing interventions and/or policy options are modelled/simulated/compared to propose the best/optimal strategy (incl. comparing current status quo vs. a new option) □ The cost-effectiveness of a treatment or intervention is explored through hypothetical cohorts of patients or through decision-analysis techniques to estimate costs per person □ Outcomes are modelled for different treatment or therapy scenarios/options □ Issues of logistics, supply chain, distribution, scheduling are explored; including studies that highlight operational inefficiencies or poor performance □ ‘What if’ scenarios are tested, e.g. what if anti-retroviral therapy coverage was increased?
and
3) The OR problem has a healthcare delivery or public health focus
↑ or ↓	□ Health services delivery (hospital/clinical services, primary care, treatment or diagnostic options, health technology management or integration, etc.) □ Public or population health (vaccination policy, mass screening for health conditions, transmission prevention and/or reduction, etc.)
and
4) The study focuses on a low- or middle-income setting
↑ or ↓	□ Country-focused: a look-up table was provided to co-authors to determine whether a country was low income, lower-middle income or upper-middle incomeb □ Regional: Africa, sub-Saharan Africa, South East Asia, Latin America, South America, etc.

^aThis list does not cover the full extent of OR-type problems, but these criteria describe the types of OR problems of interest for this review^bAccording to World Bank classifications as of July 1, 2014. Low-income economies are defined as those with a gross national income (GNI) per capita of $1045 or less in 2013; middle-income economies are those with a GNI per capita of more than $1045 but less than $12,746; lower-middle- and upper-middle-income economies are separated at a GNI per capita of $4125