an innovative context of application and may be useful for the community of relevant policymakers, academics, and health professionals. KEYWORDS Brazilian health system, data envelopment analysis, efficiency assessment, kidney transplant 1 | INTRODUCTION End-stage renal disease is a serious public health issue in which patient survival depends on renal transplantation or renal replacement therapy, such as dialysis. 1 In the long term, however, kidney transplantation is generally more effective than dialysis in public health system costs and patient quality of life. [2][3][4][5] In Brazil, dialysis is the predominant therapy for the increasing number of cases of end-stage renal disease. 6,7 From 2010 to 2014, the number of patients on dialysis increased from 92 000 to 112 000, with the Brazilian Public Health System (SUS) financing approximately 85% of treatments. 8 Brazil is also 1 of the most active countries in absolute numbers of transplanted organs, with an increasing number of transplants. Its health sector requires substantial public investment, because SUS fully funds more than 90% of transplants performed nationwide. 9Kidney transplantation from deceased donors is the most common mode of solid organ transplantation and requires confirmation of brain death diagnosis and family consent. In 2016, the estimated population needing kidney transplants exceeded the number performed by 45%. 9 Other challenges include the poor infrastructure of public hospitals, crowded intensive care units (ICUs), broken equipment, insufficient health care professionals, and delays in laboratory tests. [9][10][11] In addition, the sector faces an increased demand for SUS services 12-14 and a tight federal health budget. 15 Lastly, the size of Brazil's territory amplifies managerial complexity, with demographic and socioeconomic disparities across states reflected in contrasting availabilities of health resources. 2,16,17 Such a context highlights the importance of assessing how scarce public resources are allocated.In this context, the present study uses data envelopment analysis (DEA) to estimate the technical and scale efficiency (SE) of Brazilian states for kidney transplants performed by SUS from 2013 to 2015. Its general objective is to rank Brazilian states by their technical efficiency scores and identify those operating at an optimal, oversized or undersized scale. Two secondary objectives are to identify states with input idle capacity and to report productivity changes during the period of analysis.Data envelopment analysis is a mathematical method that compares decision making units (DMUs) with similar production processes-units using the same type of inputs to generate analogous outputs, albeit in different amounts. 18,19 The method uses a benchmarking approach that specifies for each inefficient unit an efficient peer as a managerial reference.In contrast to the numerous efficiency studies in other health care fields-mainly using nonparametric methods such as DEA 20-23 -the literature for organ donation and transplant...