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© Colin Potts B1-1 Organizational approaches to requirements Colin Potts Georgia Tech.

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Presentation on theme: "© Colin Potts B1-1 Organizational approaches to requirements Colin Potts Georgia Tech."— Presentation transcript:

1 © Colin Potts B1-1 Organizational approaches to requirements Colin Potts Georgia Tech

2 © Colin Potts B1-2 The role of systems in organizations l An organization is the context for the system’s functions »Organization provides rationale for system l Some theoretical perspectives on organizations view them as systems »Sociotechnical systems theory »IS design is mixture of Human Activity System (HAS) redesign & technical design HAS 1 HAS 2 IS

3 © Colin Potts B1-3 Overview: SSM & BPR l Soft Systems Methodology (SSM) »A methodology for understanding a HAS and stating recommendations for change »Not specific to IS »Analysis of HAS “pushes” change »Origins in STS action research l Business Process Reengineering (BPR) »Philosophy of HAS improvement; not a single methodology »HAS is a collection of controllable processes »Technology may “pull” HAS redesign »Origins in Quality- Improvement movement practice

4 © Colin Potts B1-4 Soft systems methodology l Collection (not rigid sequence) of interlinked analysis activities Outward-directed (“real-world”) activities Inward-directed (“systems”) activities Problem situation unstructured Problem situation expressed Root definitions Conceptual models Real-world/ system comparison Feasible/ desirable changes Implementation

5 © Colin Potts B1-5 Rich pictures l A sketch illustrating the current situation

6 © Colin Potts B1-6 CATWOE: stakeholder types l The HAS is described in terms of six key attributes: C= Client/customer (Who are beneficiaries of HAS?) A= Actors (Who perform activities within the HAS?) T= Transformation (What does the HAS do?) W= Weltanschauung / worldview (What are the key assumptions behind the HAS?) O= Owner (Who owns the HAS and can cause it to cease?) E= Environment (What constraints exist on how the HAS works?)

7 © Colin Potts B1-7 CATWOE Example: Meeting scheduling l C:Senior mgt. & office workers l A: Office workers & admin. assts. l T: Satisfy time utilization for teamwork l W:Busy people; coordination a pain l O: Senior mgt. / IS dept. l E: Calendar; corporate values

8 © Colin Potts B1-8 Writing a root definition l Textual definition of HAS working in CATWOE attributes: A system, owned by senior management and the IS department, operated by office workers and administrative assistants to utilize their time effectively for teamwork within the constraints of the calendar and corporate values.

9 © Colin Potts B1-9 Conceptual modeling in SSM l Model what is “systemically desirable” »Informal flow diagram call mtg identify prefs monitor & control time make resources available negotiate schedule need to meet indiv. working prefs. calendar resource constraints

10 © Colin Potts B1-10 Levels in SSM l Each subsystem of the conceptual model may be decomposed as a HAS

11 © Colin Potts B1-11 Comparing the model with the world l Does the systemically desirable HAS correspond to the real-world HAS? »E.g. is conceptual model consistent with rich picture? –obviously not a formal analysis process »If not, where can improvements be made? –SSM does not have methods for reaching consensus on change »and what should an IS do to improve HAS?

12 © Colin Potts B1-12 Team Exercise: “Quick-and- dirty” SSM l For the example system: »As a class: (1) discuss the HAS context »In teams of 2-3: (2) Draw a rich picture (3) Discuss & write root definition for HAS (4) Draw a conceptual model (top level) (5) Identify v. high-level IS requirements »As a class: (6) Discuss what you produce

13 © Colin Potts B1-13 SSM: How to find out more l Several books. »Checkland & Scholes: Soft Systems Methodology in Action –Classic, but not specific to IS »Patching: Practical Soft Systems Analysis –More of an action guide »Stowell & West: Client-Led Design –Specific to IS, but not strictly SSM

14 © Colin Potts B1-14 Business process reengineering (BPR) l Basic thesis: an organization operates through a series of processes »Repeatable activities, roles, procedures & rules »Processes can be modeled, supported & “enacted” l HAS is improved by redesigning processes Scope of improvement Local optimization (e.g. TQM) Radical redesign (e.g. BPR)

15 © Colin Potts B1-15 The role of IS in BPR l Needs “pull” vs. technology “push” Process “What” “How” possible IS identify how IS can support process “How” potential technology “Where” Candidate processes select processes that technology can support

16 © Colin Potts B1-16 Organizational use cases l Use case = standard interaction between system and its environment »For an organizational use case, the system is a HAS, envt. is the business envt. l Dual models (same concepts used) »“is”: how things are done »“ought”: envisioned improvement

17 © Colin Potts B1-17 Example use cases for library member of public librarian publisher.... circulation membership mgt. stock mgt.

18 © Colin Potts B1-18 Categories of business object

19 © Colin Potts B1-19 Example object model l E.g. borrowing a book member of public customer service assistant borrowing policy library patron book

20 © Colin Potts B1-20 Interaction diagrams Cust. Svc. asst. Borrowing policy PatronBook Member of public presents books Customer service assistant checks membership card Borrowing policy checks that member of public is library patron in good standing Customer service assistant records books to be borrowed Borrowing policy updates book record Customer service assistant tells borrower due date

21 © Colin Potts B1-21 Envisioning new processes l Consider possible use cases in an IS- supported HAS »Use analogies »Standard optimizations l For example »How is a library like a gas station? –Borrowing stations like gas pumps? »Remove assistant by having unattended check-out station

22 © Colin Potts B1-22 Team exercise: BPR use cases l For the standard example: »as a class: (1) Decide on a single business process »in groups of 2-3: (2) Identify & categorize objects for process (3) Draw an interaction diagram (4) Envision new system & describe to class

23 © Colin Potts B1-23 BPR: How to find out more l Several books »Hammer & Champy: Reengineering the Corporation »Morris & Brandon: Reengineering your Business »Johansson et al: Business Process Reengineering »Jacobson et al: The Object Advantage

24 © Colin Potts B1-24 Organizational methods: conclusion l Basic goal »Understand the context »Only then determine whether a system is necessary, and if so where its boundary should be l Preconditions »Sense that something’s wrong or that an opportunity beckons »No clear technical problem yet apparent

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