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Fig. 10.1 The basic YAWL organizational model structure (from the perspective of a unique
participant)

In contrast, Fig. 10.1 shows a representation of the model from the perspective of
one (unique) participant, so that the relationship between a particular participant
and the various organizational entities can be seen (these relationships are further
explained below). To maintain flexibility in the model, a participant’s relationship
to the other entities is not enforced; thus, a simple set of participants is sufficient
to allow resourcing of work items in YAWL. However, several of the resource pat-
terns cannot be achieved without the use of the other entities in the model. Those
entities are:

Role: Generally, a role is a duty or set of duties that are performed by one or
more participants. For example, bank teller, police constable, credit officer, audi-
tor, properties manager, and junior programmer are all examples of roles that may
be carried out within an organization. There may be several participants perform-
ing the same role (e.g., a bank may have a number of tellers), so a typical role in
an organizational model may contain a number of participants. Conversely, a cer-
tain participant may perform multiple roles. Therefore, a role may be considered
as a grouping of participants who share the same (or similar) duties within an
organization. Further, a role may belong to a larger, more general role (e.g., the
roles junior teller and senior teller may both belong to a more general role called
‘teller’). In the model, a participant may perform zero or more roles, and a role
may belong to zero or one other roles. A role may be included in the distribution
set for a task at design time, meaning that all of the participants performing that
role (or any of its sub-roles) are to be considered as potential recipients of a work
item created from the task at runtime.