Patients admitted to the hospital on the weekend have been shown to experience worse outcomes compared to those admitted on weekdays. This weekend effect has been observed numerous times across multiple health care settings. However, whether patient characteristics (patients admitted on the weekend may be more severely ill) or system factors (less staffing and certain services may not be available on the weekend) are primarily responsible remains debated. In this systematic review and meta-analysis including 68 studies, researchers found a pooled odds ratio for weekend mortality of 1.16. Moreover, the weekend effect in these studies was more pronounced for elective rather than unplanned admissions. They conclude that the evidence suggesting that the weekend effect reflects worse quality of care is of low quality. A past PSNet perspective discussed the significance of the weekend effect with regard to cardiology.