Exploring emergency department 4-hour target performance and cancelled elective operations: a regression analysis of routinely collected and openly reported NHS trust data.

Objective: To quantify the effect of intra-hospital patient flow on Emergency Department (ED) performance targets and indicate if the expectations set by the NHS England five year forward review are realistic in returning emergency services to previous performance levels. Design: Linear regression analysis of routinely reported trust activity and performance data using a series of cross-sectional studies. Setting: NHS trusts in England submitting routine nationally reported measures to NHS England. Participants: 142 acute non-specialist trusts operating in England between 2012 and 2016. Main outcome measures: The primary outcome measures were: proportion of four-hour waiting time breaches and cancelled elective operations. Methods: Univariate and multivariate linear regression models were used to show relationships between the outcome measures, and various measures of trust activity including: empty day-beds, empty night-beds, day-to-night bed ratio, ED conversion ratio and delayed tran...