Because of the ever-increasing prevalence of joint replacement, it is important that patient outcomes after surgery are continuously reviewed and monitored, with the aim of optimising outcomes after surgery. Of central importance in assessing outcomes is choosing the most appropriate outcome measure. This article reviews five methods of assessing outcomes after hip arthroplasty, namely radiographic analysis, implant survivorship analysis, surgeon-based outcome measures, performance-related assessment and patient-reported outcome measures. The relative strengths and weaknesses of each method of assessment are discussed, with the aim of aiding the surgeon or researcher in choosing an outcome measure when designing a clinical trial.