Interesting study in BMJ Quality & Safety journal that looks at ranking hospitals and whether we gain reliability by using composite rather than individual indicators. Despite widespread use of quality indicators, it remains unclear to what extent they can reliably distinguish hospitals on true differences in performance. Rankability measures what part of variation in performance reflects ‘true’ hospital differences in outcomes versus random noise. This study sought to assess whether combining data into composites or including data from multiple years improves the reliability of ranking quality indicators for hospital care. The study found that combining multiple years or into multiple indicators results in more reliable ranking of hospitals, particularly compared with mortality and acute readmission in single years, thereby improving the ability to detect true hospital differences. The composite measures provide more information and more reliable rankings than combining multiple years of individual indicators.