A stochastic programming model for outpatient appointment scheduling considering unpunctuality

•This paper addresses the outpatient scheduling problem considering unpunctuality (OS-U) by developing a stochastic programming model.•The model is solved by using Benders decomposition combined with the sample average approximation (BD-SAA) technique to determine the global optimal schedule.•Considering unpunctuality, the set of optimal appointment intervals still takes the shape of dome.•The no-show probability has a greater influence on system performances in an OS-U system than those in an outpatient scheduling problem with strict-punctuality (OS-P system).