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1 Introduction 5
execution may result in its adaptation. Adaptation may involve some modeling,
which then may lead to a new or revised version of the business process for
which the life-cycle starts again. Because of the automated support for managing
the business process life-cycle, businesses can rapidly adapt to their ever-changing
environment.
Much has been written about business processes; however, there is a lack of con-
sensus about how they are best described for the purposes of analysis and subsequent
automation. This has resulted in a plethora of approaches for capturing business pro-
cesses, though not all are intended to support direct automation. There are two main
reasons to which this situation can be attributed:
Business processes can be complex. Their specification may involve capturing
complex ordering dependencies between tasks and complex resourcing strate-
gies. Process modeling languages tend to lack the concepts to be able to deal
with the broad range of requirements one may encounter when trying to precisely
capture business scenarios.
Standardization efforts in the field have essentially failed. One may argue that
this is the result of the standardization processes being partly driven by vested
business interests. Whatever the reason, it is clear that today’s standards lack
widespread adoption and suffer from all kinds of technical problems.
The inherent complexity of business processes and the question of what fundamental
concepts are necessary for business process modeling gave rise to the develop-
ment of a collection of workflow patterns. These patterns describe process modeling
requirements in an implementation independent manner.
In this chapter, it is shown how the workflow language YAWL and its correspond-
ing system emerged from the Workflow Patterns Initiative. However, before doing
so, the role of models in BPM is discussed and some of the standard approaches are
reviewed.

1.2 On the Role of Models in BPM

Models can serve different purposes in BPM.
First of all, models may aim at providing insight. When developing or improving
an information system, it is important that the different stakeholders get insight into
the processes at hand and the way that these processes can or should be supported.
Models can be used to discuss requirements, to support design decisions, and to
validate assumptions. Moreover, the modeling process itself typically provides new
and valuable insights, because the modeler is triggered to make things explicit.
Second, models may be used to analyze the system and/or its processes. Depend-
ing on the type of model, particular types of analysis are possible or not. In the
context of BPM, analysis may focus on the business processes or on the informa-
tion system itself. For example, the performance of a system (e.g., response times)
is not the same as the performance of the processes it supports. Traditionally, most