The effect of exceptions in business processes

Business process models can be used to describe the way in which work is done in an organization. Typically, business process models (implicitly) distinguish between the normal flow of work through the organization and exceptions to the normal flow that are expected to occur incidentally. However, business processes often present an idealized view. When looking at the way in which the work is actually performed, unexpected exceptions to the normal flow of work - exceptions that are not modelled in the business process model - also occur. This paper studies the effect that exceptions have on the operational performance of an organization and in particular on the throughput time of a process. The results show that exceptions are related to worse operational performance in terms of a longer throughput time and that unexpected exceptions lead to a stronger increase in throughput time than expected exceptions. The results also show that there are different types of exceptions, which have different effects on operational performance. These results have important implications on the policies that should be followed with respect to allowing for different types of exceptions in practice.