1 (re)designing workflows tips and tricks. wil van der aalst eindhoven university of technology...
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(Re)designing workflows Tips and tricks.
Wil van der Aalst
Eindhoven University of TechnologyFaculty of Technology ManagementDepartment of Information and TechnologyP.O. Box 513 5600 MB EindhovenThe [email protected]
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Designing a workflow
What?
How?
By whom?
begin
realization
objectives
tasks andprocesses
resources andscheduling
analyze
analyze
analyze
text
resource classificationallocation rules
process definition
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Guidelines
• Start with the identification of a case.What is the case?
– A case is often initiated by a customer (internal or external!)
– The process adds value to a case.
– A case has a life-cycle with begin and end.
– A case cannot be divided, but the work can.
• Determine the scope of the process as soon as possible.
• Determine the goal of a process (added value).
• Ignore the existence of resources during the design of a process.
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Guidelines (2)
• Workflow modeling is an iterative process– don't be afraid to make mistakes !!
– tasks are split and joined during the process
– use hierarchy: divide and conquer
• During the process a task should become a Logical Unit of Work (LUW)
– atomic: commit or rollback
– a task is executed by the same person, at the same time, at the same place
– avoid setup times (not too small)
– avoid large chucks (commit work should be limited)
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Extracting information from an existing process.
• Follow (paper) documents.
• Identify communication between people, teams and departments.
• Identify regular communication patterns (dialog/protocol).
A B Crequest
commandinformation
request
information
responsemessagesequence
chart
A
B
C D
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Reengineering workflows• BPR: fundamental, radical, dramatic, process.
• Ignore existing processes and organization.
• Symptoms of a sick process:– too many cases (in-process-inventory)
– (throughput time / service time)-ratio is too high
– service level (% in time) is too low
• Key performance indicators:
– throughput time, waiting time, service level
– occupation rate, number of cases, ...
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Guidelines for BPR
• Check the necessity of each task.
• Appoint a process manager.
• Appoint case managers.
• (Re)consider the size of each task.
• (Re)consider the trade-off between a generic process and multiple versions of the same process.
• (Re)consider the trade-off between a generic task and multiple specialized tasks.
• Try to introduce more parallelism.
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Guidelines for BPR (2)
• Investigate new opportunities as a result of modern technology.
• Optimize communication structure.
• Do not automate paper workflows!
• An electronic document is everywhere and nowhere.
• Use resources as if they are in the same room.
• Use a resource for what it is good at.
• Maintain as much flexibility as possible for the future.
• Avoid setup times by clustering tasks.
• Avoid setups and exploit routine by clustering cases.
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Design criteria
A process design is evaluated on the basis of four
key issues:
• time
• quality
• costs
• flexibility
Often there is a trade-off!
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Design criterion 1: Time
• Throughput time is composed of:
– service time (including set-up)
– transport time (can often be reduced to 0)
– waiting time
» sharing of resources (limited capacity)
» external communication (trigger time)
• There are several ways to evaluate throughput/waiting time:
– average
– variance
– service level
– ability to meet due dates
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Design criterion 2: Quality
• External: satisfaction of the customer
– Product: product meets specification/expectation.
– Process: the way the product is delivered (service level)
• Internal: conditions of work
– challenging
– varying
– controlling
There is often a positive correlation between external and
internal quality.
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Design criterion 3: Costs
• Type of costs
– fixed or variable,
– human, system (hardware/software), or external,
– processing, management, or support.
Note the trade-off between human/system-related costs.
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Design criterion 4: Flexibility
• The ability to react to changes.
• Flexibility of
– resources (ability to execute many tasks/new tasks)
– process (ability to handle various cases and changing workloads)
– management (ability to change rules/allocation)
– organization (ability to change the structure and responsiveness to wishes of the market and business partners)
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(1) Check the necessity of each task
• Every "check task" may be skipped: a trade-off between the costs of the check and the costs of not doing the check.
A B
check
A B
A B
check
auto-select
(T+,Q-,C+/-)
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(2) Appoint process/case managers• A process manager monitors a process to see whether
there are bottlenecks, capacity problems and delayed cases. Management instruments: motivating the people involved in the process and control parameters.
• Case managers are assigned to a case. They are responsible and execute as many tasks as possible for the case. Benefits:
– commitment
– reduction of setup time
– one contact person
(Q+)
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(3) (Re)consider the size of each task
Pros: less work to commit, allows for specialization.Cons: setup time, fragmentation, less commitment.
Pros: setup reduction, no fragmentation, more commitment.Cons: more work to commit, one person needs to be qualified for both parts.
Also a trade-off between the complexity of the process
and the complexity of a task. (T+,F-)
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(4) Trade-off: one generic process or multiple versions
A
B
A
B
A\BA B
B\A
Issues: simplicity, efficiency, controllability, maintainability, ...(F+/-)
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(5) Trade-off: one generic task or multiple specialized tasks
• Similar considerations.
• Specialization may lead to:
– the possibility to improve the allocation of resources
– more support when executing the task
– less flexibility
– a more complex process
– monotonicity
(T+,F-)
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(6) Introduce as much parallelism as possible• More parallelism leads to improved performance:
reduction of waiting times and better use of capacity.
• Two types of parallelism: semi and real parallelism.
• IT infrastructures which allow for the sharing of data and work enable parallelism.
A B
A
B (T++)
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(7) Investigate opportunities of IT• DBMS: sharing of data
– An electronic document is everywhere and nowhere!
• Network technology:– communication: e-mail, WWW, ...
– distribution of information: transportation of data is fast, cheap and convenient
• Automation of task or automated support of tasks
• Examples:– parallel (sharing of data)
– customer involvement (sending forms via the WWW)
– form synchronous to asynchronous communication
– risk analysis based on historical data Do
not a
utom
ate
pape
r w
orkf
low
s!
(T+,Q+/-,C+/-,F-)
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(8) Improve the allocation of resources• Use resources as if they are in one room: avoid (at any time!)
the situation where one group of people is overloaded and another (similar) group is waiting for work.
(T+,Q-)
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• Let people do work that the are good at. However, avoid inflexibility as a result of specialization!
• Stimulate resources to build routine.
• When allocating work to resources, consider the flexibility in the near future.
• Avoid setups as much as possible. There are two kinds of setups: (1) case setups and (2) task setups.
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(9) Improve communication structure• Reduce the number of messages to be exchanged
between the process and the environment.
• Try to automate the handling of messages (send/receive).
• Avoid communication errors (EDI,WWW).
• If possible, use asynchronous instead of synchronous communication.
(T+,Q+,C+/-,F-)
A B Crequest
commandinformation
requestinformation
response
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(10) Order tasks based on cost/effect
• Consider the class of “knock-out processes”, e.g., hiring people, handling claims, etc.
• Postphone expensive tasks until the end.
• Execute highly selective tasks first.
• In other words: order the tasks using the ratio “costs/effect”.
(T+,C-)