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CS 501: Software Engineering

Lecture 3

Feasibility Studies

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Administration

Assignment 0: preliminary survey

• See the Assignments Web page for instructions

• Submit by Monday, February 6

• Send questions to Sadat Shami

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Administration

Projects:

Announcements by project groups

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Administration

Project teams:

• If you do not have a team, you can meet after class

• If you are having difficulty finding a team send email to cs501-l@lists.cs.cornell.edu

• We may ask teams to add extra members

• If you have definitely chosen a project and reached agreement with your client, send email to cs501-l@lists.cs.cornell.edu with the names of your team members

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Feasibility Study

A feasibility study is a study made before committing to a project.

A feasibility study leads to a decision:

go aheaddo not go aheadthink again

In production projects, the feasibility study often leads to a budget request.

In research, a feasibility study is often in the form of a proposal.

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Why are Feasibility Studies Difficult?

Benefits are usually very hard to quantify (e.g., NSDL).

Approach is usually ill-defined. Estimates of resources needed and timetable are very rough (e.g., eCornell).

Organizational changes may be needed (e.g., Copyright deposit system).

Therefore, feasibility studies rely heavily on the judgment of experienced people.

Mistakes made at the beginning are the most difficult to correct.

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Why are Feasibility Studies Difficult?Advocacy

Advocacy is needed to build enthusiasm for a large project: to convince an organization to undertake an expensive, complex project with many risks.

Enthusiasm is good, but enthusiasts usually emphasize potential benefits and downplay risks.

People carrying out the feasibility study and making the decision often have a vested interest in the project going ahead, e.g., financial gain, career development.

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The Decision Maker's Viewpoint

A senior member of an organization must decide whether to begin a major software project. What information is needed?

Client: Who is this project for?

Scope: What are the boundaries of the project?

Benefits: What are the benefits? Can they be quantified?

Technical: Is there at least one technical way to carry out the project?

Resources: What are the estimates of staff, time, equipment, etc?

Alternatives: What are the options if the project is not begun?

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The Decision Maker's ViewpointWhere are risks? Can they be minimized?

Technical

• There must be an outline plan with a rough timetable and staff allocation.

• The plan must have a very large margin for contingencies. (Projects typically require twice the staff and/or time envisaged in the feasibility plan.)

External

• Every system interacts with others. Are the others committed to the necessary efforts?

• Where are the external pressures and obstacles?

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Example 1: Benefits of the National Science Digital Library (NSDL)

Concept

Create a comprehensive digital library for all aspects of science education, where science and education are both defined very broadly.

The National Science Foundation studied potential benefits for five years before going ahead.

It came to the conclusion that, even though the benefits could not be quantified, the potential was sufficient to justify a major program.

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Example 1: NSDL Feasibility Timetable

1996 Vision articulated by NSF's Division of Undergraduate Education

1997 National Research Council workshop

1998 SMETE-Lib workshop

1999 NSDL solicitation

2000 6 demonstration projects of the core system

2001 Core integration system funded

Five years from concept to decision to definitely go ahead.

Note: Since going ahead, the NSF has been less careful about continuing to review the feasibility study after each major iteration.

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Example 2: U.S. Government Agency(Decision before Feasibility Study)

Outline Description

A U.S. government agency, which manages huge numbers of documents and other records, has been very slow in moving from a paper based approach to managing digital documents.

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Example 2: Chronology

• A scientific computing center at University of California was commissioned to develop a prototype system to demonstrate technology.

• Funds were approved by Congress to "procure" a major computer system.

• The National Academy of Sciences was commissioned to report on the technical approach to be followed and the results of the University of California prototype (feasibility study).

Note: The decision to go ahead was made and the budget approved before the feasibility study was begun.

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Example 2: National Academy Report

The National Academy study finds:

• The computer system is technically feasible.

• The University of California prototype is promising but incomplete.

• Agency needs stronger technical staff.

The study was not asked to comment on external factors, but discovered major weaknesses in the agency's management structure and organizational skills.

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Example 2: Obvious Problems

Organizational:

• Agency senior management clearly not ready to lead a very large project that will completely change the agency

• No thought given to the workflow and job changes that will affect almost every member of staff

Preparation:

• No preliminary study made of volumes or kinds of data; nor of the very complex access policies

Complexity

• Major changes in the requirements and design are inevitable once the system goes into production and has real users

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Example 2: National Academy Report: Technical Recommendations

The study recommends a phased approach:

1. System architecture created by iterative refinement to create a Phase 1 design.

2. Followed by sequential implementation using the Phase 1 design

[Note that this is the same phasing used in the vector graphics for Basic project discussed in Lecture 2.]

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Example 2: Prototype and Phased Development

• A prototype is not released to users, except experimentally

• In phased development, each phase is released into full production

UC prototype

Build phase 1

Build phase 2

Demonst-ration only

Phase 1 production

Phase 2 production

Developers

Users

Iterative process

Sequential process

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Example 2: Dilemma

• Agency does not want to return money to Congress

• National Academy study was paid for by agency and restricted to technical considerations

• The fundamental problem lies at the senior management level

[A phased approach over many years might possibly work, but only after the organizational problems are addressed.]

• The agency, adopted a pure waterfall model, put out a Request for Proposal for the Requirements, and placed a major contract with a software house.

This is a disaster in the making.

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Feasibility Study: Scope

Scope expresses the boundaries of the system:

• It will include a list of included functions

• It will exclude a list of excluded functions

• It depends on a list of dependencies

• It replaces a list of functions to be replaced

Confusion over scope is a common reason for clients to be dissatisfied with a system.

"Is that all you planned to do?" "But I assumed that you were going to do xyz." "I can't use the system without abc."

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Example 3: Library of CongressConfusion over Scope

• The Library of Congress required a repository system to store and make accessible very large amounts of highly varied material over long periods of time.

• An outside organization (CNRI) built a repository system to store and manipulate complex digital objects

• Nobody built the sub-systems needed to organize, validate, and to load material into the repository.

• The Library of Congress expected the repository system to include this sub-system. CNRI considered it external to the repository system

A good feasibility study would have seen this confusion.

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Feasibility Study: Benefits

Why is this project proposed? Can you quantify the benefits?

Organization benefits

• Create a marketable product

• Improve the efficiency of an organization (e.g., save staff)

• Control a system that is too complex to control manually

• New or improved service (e.g., faster response to customers)

• Safety or security (e.g., EPIRB)

Professional benefits are not the reason for doing a project

• Get a good grade on CS 501

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Feasibility Study: Technical

A feasibility study needs to demonstrate that the proposed system is technically feasible. This requires:

• a rough outline of the requirements

• a possible system design (e.g., database, distributed, etc.)

• estimates of numbers of users, data, transactions, etc.

• possible choices of software to be acquired or developed

These very rough numbers are fed into the provisional plan that is used to estimate the staffing, timetable, equipment needs, etc.

The technical approach actually followed may be very different.

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Feasibility Study: Planning and Resources

The feasibility study should include an outline plan:

• Estimate the staffing and equipment needs, and the preliminary timetable

• Identify major decision points

• Identify interactions with and dependences on external systems

• Provide a preliminary list of deliverables and delivery dates

Lecture 4 is about planning techniques.

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Feasibility Study: Alternatives and Risks

A feasibility study should identify alternatives and risks.

Alternatives

• Continue with current system, enhance it, or create new one?

• Develop in-house, or contract out? (How will a contract be managed?)

• Phases of delivery and possible points for revising plan.

Risks

• What can go wrong?

• How will problems be identified (visibility)?

• What are the fall-back options?

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Techniques for Feasibility Studies

Give client appreciation of system:

demonstration

mock-up

walk through

Outline budget:

n people for m months at $x per month

equipment, buildings, etc.

Phases/milestones:

deliverables at approximate date

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Feasibility Report

A written document

• For a general audience: client, financial management, technical management, etc.

• Short enough that everybody reads it.

• Long enough that no important topics are skipped.

• Details are often included in supporting documents.

It should be a well written, well presented document.

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Feasibility Study: Decision

The implications of the Feasibility Report must be understood by all key people.

Different organizations and senior managers have different styles, e.g.,

• Monitor the team and the process

• Rely on detailed reading of written report

• Rely on face-to-face questioning of knowledgeable people

But they must understand the decision.

A report that is never read and understood is useless.

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CS 501: Client

In CS 501, you have two clients:

• The client for the project

• The professor for the course

Satisfy the client and the professor is pleased!

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CS 501: Resources

Examples: CS 501

Staff: 5 to 7 students, with some help. How many hours per week? What skills do people have?

Time: Must be completed by end of semester, including operational system, documentation, presentation

Equipment and software: What special needs are there?

Client: Will the client be sufficiently available and helpful?

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CS 501: Obstacles

CS 501 projects

Start-up time. Creating a team, scheduling meetings, acquiring software, learning new systems, ...

Business considerations. Licenses, trade-secrets, ...

Too ambitious. Nothing to show at the end of the semester...

Changing circumstances. Client leaves the university, ...

What else?

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CS 501: How to Minimize Risk?

CS 501 Projects

• Several target levels of functionality: required, desirable, optional phases

• Visible software process: intermediate deliverables

• Good communication within team and with Teaching Assistant

Good processes lead to good software

Good processes reduce risk

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CS 501: Feasibility Report

Specific Requirements for the Feasibility Report

• Outline plan, showing principal activities and milestones (to be discussed on Thursday).

• Discussion of Business Considerations (see Projects page on the course Web site).

• Risk analysis. What can go wrong? What is your fall back plan?

*