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Eindhoven University of Technology Faculty of Technology Management Department of Information and Technology P.O. Box 513 5600 MB Eindhoven The Netherlands w.m.p.v.d.aalst @ tm .tue.nl. (Re)designing workflows Tips and tricks. Wil van der Aalst. Designing a workflow. begin. analyze.
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Eindhoven University of Technology Faculty of Technology Management Department of Information and Technology P.O. Box 513 5600 MB Eindhoven The Netherlands w.m.p.v.d.aalst@tm.tue.nl (Re)designing workflows Tips and tricks. Wil van der Aalst
Designing a workflow begin analyze What? analyze objectives How? text analyze tasks and processes By whom? process definition resources and scheduling realization resource classification allocation rules
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.
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)
Extracting information from an existing process. • Follow (paper) documents. • Identify communication between people, teams and departments. C A D B • Identify regular communication patterns (dialog/protocol). A B C request command information information message sequence chart request response
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, ...
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.
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.
Design criteria A process design is evaluated on the basis of four key issues: • time • quality • costs • flexibility Often there is a trade-off!
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
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.
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.
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)
Trade-off Costs Time Flexibility Quality (T+/-,Q+/-,C+/-,F+/-)
A B check A B auto-select A B check (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. (T+,Q-,C+/-)
(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+)
(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-)
(4) Trade-off: one generic process or multiple versions A B A B A\B A Ç B B\A Issues: simplicity, efficiency, controllability, maintainability, ... (F+/-)
(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-)
A B A B (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. (T++)
(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 automate paper workflows! (T+,Q+/-,C+/-,F-)
(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-)
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.
A B C request command information information request response (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-)
(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-)