1. 6 REQUIREMENTSDISCOVERY C H A P T E R
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2. Introduction to Requirements Discovery
Requirements discovery includes those techniques to be used by systems analysts to identify or extract system problems and solution requirements from the user community.
Problem analysis is the activity of identifying the problem, understanding the problem (including causes and effects), and understanding any constraints that may limit the solution.
Teaching Notes
This chapter focuses on the techniques and activities for eliciting system requirements as well as how to properly validate and document requirements. The authors have placed an emphasis on this chapter because recent studies have shown that as many as 80% of all system development failures can be traced back to problems with requirements.

3. Introduction to Requirements Discovery
A system requirement (also called a business requirement) is a description of the needs and desires for an information system. A requirement may describe functions, features (attributes), and constraints.
No additional notes.

4. Types of Requirements
A functional requirement is a function or feature that must be included in an information system in order to satisfy the business need and be acceptable to the users.
A nonfunctional requirement is a description of the features, characteristics, and attributes of the system as well as any constraints that may limit the boundaries of the proposed solution.
Teaching Notes
A functional requirement is an action of the system and usually is written using an action verb phrase. For example:
·         The system should process a checking account deposit
·         The system should calculate the GPA for a student
·         The system should capture the account holder identification information
Examples of nonfunctional requirements.
·         be user friendly
·         be able to accommodate users at different physical locations
Teaching Tips
Have students give examples of different types of requirements and classify this as functional versus nonfunctional.

5. Types of Nonfunctional Requirements
operate, as well as the type and degree of security that must be provided.
happen?
increase profits.
What are the budgetary limits?
handling (backups, offsite storage, etc.) of the data?
Performance
Information
Control (and Security)
Requirement Type
Explanation
Performance requirements represent the performance the system is required
to exhibit to meet the needs of users.
What is the acceptable throughput rate?
What is the acceptable response time?
Informatio
n requirements represent the information that is pertinent to the
users in terms of content, timeliness, accuracy, and format.
What are the necessary inputs and outputs? When must they
What is the required data to be stored?
How current must the information be?
What are the interfaces to external systems?
Economy requirements represent the need for the system to reduce costs or
What are the areas of the system where costs must be reduced?
How much should costs be reduced or profits be increased?
What is the timetable for development?
Control requirements represent the environment in which the system must
Must access to the system or information be controlled?
What are the privacy requirements?
Does the criticality of the data necessitate the need for special
Teaching Tips
Review each category and have the students give additional examples.
Teaching Notes
Other classifications of requirements exist and are published by IEEE and in Military standards. We chose to use PIECES to be consistent and reinforce the theme of the textbook.

6. Types of Nonfunctional Requirements (concluded)
Requirement Type
Explanation
Efficiency
Efficiency requirements represent the systems ability to produce outputs
with minimal waste.
Are there duplicate steps in the process that must be eliminated?
Are there ways to reduce waste in the way the system uses it
resources?
Service
Service requirements represent needs in order for the system to be
reliable, flexible, and expandable.
Who will use the system and where are they located?
Will there be different types of users?
What are the appropriate human factors?
What training devices and training materials are to be included in
the system?
What training devices and training materials are to be developed
and maintained separately from the system, such as stand- alone
computer based training (CBT) programs or databases?
What are the reliability/availability requirements? Ho
w should the system be packaged and distributed?
What documentation is required?
No additional notes.

7. An Ambiguous Requirements Statement
Create a means to transport a single
individual from home to place of work.
Management
Interpretation
I T
User
Teaching Tips
Try to give other examples of a requirements statement that can be interpreted many ways. These can relate to homework assignments, current events, or normal household chores.

8. Results of Incorrect Requirements
The system may cost more than projected.
The system may be delivered later than promised.
The system may not meet the users’ expectations and that dissatisfaction may cause them not to use it.
Once in production, the costs of maintaining and enhancing the system may be excessively high.
The system may be unreliable and prone to errors and downtime.
The reputation of the IT staff on the team is tarnished because any failure, regardless of who is at fault, will be perceived as a mistake by the team.
No additional notes.

9. Relative Cost to Fix an Error
Phase in Which Found
Cost Ratio
Requirements 1
Design
3-6
Coding 10
Development Testing
15-40
Acceptance Testing
30-70
Operation
Teaching Notes
Table based on work by Barry W. Boehm, a noted expert in information technology economics. Based on these findings, an erroneous requirement that goes undetected and unfixed until the operation phase may cost 1,000 times more than if it were detected and fixed in the requirements phase!

10. Criteria to Define System Requirements
Consistent
Complete
Feasible
Required
Accurate
Traceable
Verifiable
Teaching Notes
The goal of the systems analyst is to define system requirements that meet the following criteria:
·         Consistent  the requirements are not conflicting or ambiguous.
·         Complete  the requirements describe all possible system inputs and responses.
·         Feasible  the requirements can be satisfied based on the available resources and constraints (feasibility analysis is covered in Chapter 9).
·         Required  the requirements are truly needed and fulfill the purpose of the system.
·         Accurate  the requirements are stated correctly.
·         Traceable  the requirements directly map to the functions and features of the system.
·         Verifiable  the requirements are defined so they can be demonstrated during testing.

11. The Process of Requirements Discovery
Problem discovery and analysis
Requirements discovery
Documenting and analyzing requirements
Requirements management
Teaching notes
The process of requirements discovery consists of four activities.

12. Ishikawa Diagram
The Ishikawa diagram is a graphical tool used to identify, explore, and depict problems and the causes and effects of those problems. It is often referred to as a cause-and-effect diagram or a fishbone diagram.
Teaching Tips
Explain concept to students. Try to do another example during lecture based on a well-known problem that most students experience – registration.

13. Requirements Discovery
Fact-finding is the formal process of using research, interviews, questionnaires, sampling, and other techniques to collect information about problems, requirements, and preferences. It is also called information gathering.
Teaching Notes
Stress that fact-finding is a technique that is used across the entire development cycle but it is extremely critical in the requirements analysis phase.
Teaching Tips
Be sure to discuss the role of ethics during the fact-finding activity.

14. Seven Fact-Finding Methods
Sampling of existing documentation, forms, and databases.
Research and site visits.
Observation of the work environment.
Questionnaires.
Interviews.
Prototyping.
Joint requirements planning (JRP).
No additional notes.

15. Documenting and Analyzing Requirements
A requirements definition document should consist of the following.
The functions and services the system should provide.
Nonfunctional requirements including the system’s features, characteristics, and attributes.
The constraints that restrict the development of the system or under which the system must operate.
Information about other systems the system must interface with.    
No additional notes.

16. Sample Requirements Definition Outline
Requirements Definition Report
1. Introduction
1.1 Purpose
1.2 Background
1.3 Scope
1.4 Definitions, Acronyms, and Abbreviations
1.5 References
2. General Project Description
2.1 System Objectives
3. Requirements and Constraints
3.1 Functional Requirements
3.2 Nonfunctional Requirements
4. Conclusion
4.1 Outstanding Issues
Appendix (optional)
Teaching Notes
There is no standard name or format for this document. In fact, many organizations use different names such as requirements statement, requirements specification, requirements definition, functional specification, etc., and the format is usually tailored to that organization’s needs. For those companies that provide information systems and software to the U.S. government, the government requires that they use the format and naming conventions specified in their published standards document MIL-STD-498[1]. Many organizations have created their own standards adapted from MIL-STD-498 because of its thoroughness and because many people are already familiar with it. In this book we will use the term requirements definition document .
[1] MIL-STD-498 is a standard that merges DOD-STD-2167A and DOD-STD-7935A to define a set of activities and documentation suitable for the development of both weapon systems and automated information systems.

17. Validating Requirements
Requirements validation is an activity that checks the requirements definition document for accuracy, completeness, consistency, and conformance to standards.
Teaching Notes
Requirements validation is performed on a final draft of the requirements definition document after all input has been solicited from the system owners and users. The purpose of this activity is for the systems analyst to ensure the requirements are written correctly.
Teaching Tip
Have students provide examples of errors the validation activity may identify.

18. Requirements Management
Requirements management is the process of managing change to the requirements.
Teaching Notes
Over the lifetime of the project it is very common for new requirements to emerge and existing requirements to change once a requirements definition document has been approved. Some studies have shown that over the life of a project as much as 50 percent or more of the requirements will change before the system is put into production.
Requirements management encompasses the policies, procedures, and processes that govern how a change to a requirement is handled. In other words, it specifies how a change request should be submitted, how it is analyzed for impact to scope, schedule, and cost, how it’s approved or rejected, and how the change is implemented if approved.

19. Sampling
Sampling is the process of collecting a representative sample of documents, forms, and records.
Determining the sample size:
Sample Size = 0.25 x (Certainty factor/Acceptable error)2
For a 90% certainty:
Sample Size = 0.25(1.645/0.10)2 = 68
Teaching Tips
Two versions of the sampling formula are provided in the textbook. The first uses a heuristic (.25) to calculate the sample size and the second replaces the (.25) with p(1-p) to reflect the knowledge of errors in the sample population. Review each with students and calculate various sample sizes using different levels of certainty.

20. Sampling Techniques
Randomization is a sampling technique characterized as having no predetermined pattern or plan for selecting sample data.
Stratification is a systematic sampling technique that attempts to reduce the variance of the estimates by spreading out the sampling—for example, choosing documents or records by formula—and by avoiding very high or low estimates.
Teaching Notes
For randomization you just randomly choose the number of sample items based on the sample size calculated.
For computerized files, stratification sampling can be executed by writing a simple program. For instance, suppose invoices were stored in a database that had a volume of approximately 250,000. If the required sample size was 25, a program could be written that prints every 10,000th record (=250,000/25).

21. Observation
Observation is a fact-finding technique wherein the systems analyst either participates in or watches a person perform activities to learn about the system.
Advantages?
Disadvantages?
Work sampling is a fact-finding technique that involves a large number of observations taken at random intervals.
Teaching Notes
This technique is often used when the validity of data collected through other methods is in question or when the complexity of certain aspects of the system prevents a clear explanation by the end-users.
Teaching Tips
Have students review The Railroad Paradox by Gerald M. Weinberg. Discuss the moral of the story.
Have students provide advantages and disadvantages of observation.

22. Observation Guidelines
Determine the who, what, where, when, why, and how of the observation.
Obtain permission from appropriate supervisors or managers.
Inform those who will be observed of the purpose of the observation.
Keep a low profile.
Take notes during or immediately following the observation.
Review observation notes with appropriate individuals.
Don't interrupt the individuals at work.
Don't focus heavily on trivial activities.
Don't make assumptions.
No additional notes.

23. Questionnaires
Questionnaires are special-purpose documents that allow the analyst to collect information and opinions from respondents.
Advantages?
Disadvantages?
Teaching Tips
Have students provide advantages and disadvantages of observation.

24. Types of Questionnaires
Free-format questionnaires offer the respondent greater latitude in the answer. A question is asked, and the respondent records the answer in the space provided after the question.
Fixed-format questionnaires contain questions that require selection of predefined responses from individuals.
Teaching Tips
Have students provide examples of both free-format and fixed-format questions.

25. Types of Fixed-Format Questions
Multiple-choice questions
Rating questions
Ranking questions
Teaching Notes
For multiple-choice questions, the respondent is given several answers. The respondent should be told if more than one answer might be selected.
For rating questions, the respondent is given a statement and asked to use supplied responses to state an opinion. To prevent built-in bias, there should be an equal number of positive and negative ratings.
For ranking questions, the respondent is given several possible answers, which are to be ranked in order of preference or experience.

26. Questionnaire Procedure
Determine what facts and opinions must be collected and from whom you should get them.
Based on the needed facts and opinions, determine whether free- or fixed-format questions will produce the best answers.
Write the questions.
Test the questions on a small sample of respondents.
Duplicate and distribute the questionnaire.
No additional notes.

27. Interviews
Interviews are a fact-finding technique whereby the systems analysts collect information from individuals through face-to-face interaction.
Advantages?
Disadvantages?
Teaching Notes
Interviewing can be used to achieve any or all of the following goals: find facts; verify facts; clarify facts; generate enthusiasm; get the end-user involved; identify requirements; and solicit ideas and opinions.
Teaching Tips
Have students provide advantages and disadvantages of interviews.

28. Types of Interviews
Unstructured interviews are conducted with only a general goal or subject in mind and with few, if any, specific questions. The interviewer counts on the interviewee to provide a framework and direct the conversation.
In structured interviews the interviewer has a specific set of questions to ask of the interviewee.
Teaching Notes
An unstructured interview frequently gets off track, and the analyst must be prepared to redirect the interview back to the main goal or subject. For this reason, unstructured interviews don't usually work well for systems analysis and design.
No additional notes.

29. Types of Interview Questions
Open-ended questions allow the interviewee to respond in any way that seems appropriate.
Closed-ended questions restrict answers to either specific choices or short, direct responses.
Teaching Tips
Have students provide examples of open-ended and closed-ended questions.

30. Procedure to Conduct an Interview
Select Interviewees
Prepare for the Interview
An interview guide is a checklist of specific questions the interviewer will ask the interviewee.
Conduct the Interview
Follow Up on the Interview
No additional notes.

31. Types of Questions to Avoid
Interview Questions
Types of Questions to Avoid
Loaded questions
Leading questions
Biased questions
Interview Question Guidelines
Use clear and concise language.
Don’t include your opinion as part of the question.
Avoid long or complex questions.
Avoid threatening questions.
Don’t use “you” when you mean a group of people.
Teaching Tips
Have students provide examples of loaded, leading, and biased questions.

32. Sample Interview Guide
Interviewee: Jeff Bentley, Accounts Receivable Manager
Date: Tuesday, March, 23, 2000
Time: 1:30 P.M.
Place: Room 223, Admin. Bldg.
Subject: Current Credit-Checking Policy
Time Interviewer Interviewee
Allocated Question of Objective Response
1 to 2 min. Objective
Open the interview:
Introduce Ourselves
Thank Mr. Bentley for his valuable time
State the purpose of the interview--to obtain an understanding of the existing credit-checking policies
5 min. Question 1
What conditions determine whether a customer’s order is approvedfor credit?
Follow-up
5 min. Question 2
What are the possible decisions or actions that might be taken once these conditions have been evaluated?
3 min. Question 3
How are customers notified when credit is not approved for their order?
No additional notes.
(continued)

33. Sample Interview Guide (concluded)
1 min. Question 4
After a new order is approved for credit and placed in the file containing orders that can be filled, a customer might request that a modification be made to the order. Would the order have to go through credit approval again if the new total order cost exceeds the original cost?
Follow-up
1 min. Question 5
Who are the individuals that perform the credit checks?
1 to 3 mins. Question 6
May I have permission to talk to those individuals to learn specifically how they carry out the credit-checking process?
1 min. Objective
Conclude the interview:
Thank Mr. Bentley for his cooperation and assure him that he will be receiving a copy of what transpired during the interview
21 minutes Time allotted for base questions and objectives.
9 minutes Time allotted for follow-up questions and redirection
30 minutes Total time allotted for interview (1:30 p.m. to 2:00 p.m.)
General Comments and Notes:
No additional notes.

34. Interviewing Do’s and Don’ts
Be courteous
Listen carefully
Maintain control
Probe
Observe mannerisms and nonverbal communication
Be patient
Keep interviewee at ease
Maintain self-control
Avoid
Continuing an interview unnecessarily.
Assuming an answer is finished or leading nowhere.
Revealing verbal and nonverbal clues.
Using jargon
Revealing your personal biases.
Talking instead of listening.
Assuming anything about the topic and the interviewee.
Tape recording -- a sign of poor listening skills.
Teaching Tips
Discuss with the students each of the items and the reasons for their classifications.

35. Communicating With the User
Listening - “To hear is to recognize that someone is speaking, to listen is to understand what the speaker wants to communicate.” (Gildersleeve – 1978)
Guidelines for Communicating
Approach the Session with a Positive Attitude
Set the Other Person at Ease
Let Them Know You Are Listening
Ask Questions
Don’t Assume Anything
Take Notes
Teaching Tips
Ask the students to comment on hearing versus listening. Ask them to give you examples.
Focus on the story by Art Linkletter and why not assuming anything is important.

36. Body Language and Proxemics
Body language is all of the nonverbal information being communicated by an individual. Body language is a form of nonverbal communications that we all use and are usually unaware of.
Proxemics is the relationship between people and the space around them. Proxemics is a factor in communications that can be controlled by the knowledgeable analyst.
Teaching Notes
Research studies have determined a startling fact — of a person's total feelings, only 7 percent are communicated verbally (in words), 38 percent are communicated by the tone of voice used, and 55 percent of those feelings are communicated by facial and body expressions.

37. Intimate zone—closer than 1.5 feet
Spatial Zones
Intimate zone—closer than 1.5 feet
Personal zone—from 1.5 feet to 4 feet
Social zone—from 4 feet to 12 feet
Public zone—beyond 12 feet
Teaching Notes
Certain types of communications take place only in some of these zones. For example, an analyst conducts most interviews with system users in the personal zone. But the analyst may need to move back to the social zone if the user displays any signs (body language) of being uncomfortable. Sometimes increasing eye contact can make up for a long distance that can't be changed. Many people use the fringes of the social zone as a ``respect'' distance.

38. Discovery Prototyping
Discovery prototyping is the act of building a small-scale, representative or working model of the users’ requirements in order to discover or verify those requirements.
Advantages?
Disadvantages?
Teaching Notes
Discovery prototyping is frequently applied to systems development projects, especially in those cases where the development team is having problems defining the system requirements. The philosophy is that the users will recognize their requirements when they see them.
Teaching Tips
Have students provide advantages and disadvantages of discovery prototyping.

39. Joint Requirements Planning
Joint requirements planning (JRP) is a process whereby highly structured group meetings are conducted for the purpose of analyzing problems and defining requirements. JRP is a subset of a more comprehensive joint application development or JAD technique that encompasses the entire systems development process.
Teaching Notes
JRP (and JAD) techniques are becoming increasingly common in systems planning and systems analysis to obtain group consensus on problems, objectives, and requirements.

40. Sponsor Facilitator Users and Managers Scribes I.T. Staff
JRP Participants
Sponsor
Facilitator
Users and Managers
Scribes
I.T. Staff
Teaching Tips
Discuss the role of each. Be sure to focus on the skills needed to be a successful JRP facilitator.

41. Steps to Plan a JRP Session
Selecting a location
Selecting the participants
Preparing the agenda
Teaching Tips
Discuss why the JRP session location should be held off-site.
Discuss why many companies opt to hire qualified JRP facilitators from outside the organization.

42. Typical room layout for JRP session
41' -
0"
30' -
Flipchart
IT Professionals & Other Observers
Users
and
Managers
JAD
Facilitator
Scribe
Workstation
(for CASE tool)
Printer
Blackboard
Overhead Projector
Computer
Projection
Device
Food & Refreshments
(for prototyping tool)
Teaching Tips
Discuss the seating arrangement of the participants as well as where the equipment is located. Also solicit the opinions of students in the way of providing refreshments. Do they think it is necessary?

43. Guidelines for Conducting a JRP Session
Do not unreasonably deviate from the agenda
Stay on schedule
Ensure that the scribe is able to take notes
Avoid the use of technical jargon
Apply conflict resolution skills
Allow for ample breaks
Encourage group consensus
Encourage user and management participation without allowing individuals to dominate the session
Make sure that attendees abide by the established ground rules for the session
No additional notes.

44. Brainstorming
Brainstorming is a technique for generating ideas during group meetings. Participants are encouraged to generate as many ideas as possible in a short period of time without any analysis until all the ideas have been exhausted.
Teaching Notes
Sometimes, one of the goals of a JRP session is to generate possible ideas to solve a problem. Brainstorming is a common approach that is used for this purpose.

45. Brainstorming Guidelines
Isolate the appropriate people in a place that will be free from distractions and interruptions
Make sure that everyone understands the purpose of the meeting
Appoint one person to record ideas
Remind everyone of the brainstorming rules
Within a specified time period, team members call out their ideas as quickly as they can think of them
After the group has run out of ideas and all ideas have been recorded, then and only then should the ideas be analyzed and evaluated
Refine, combine, and improve the ideas that were generated earlier
Teaching Tips
Be sure to discuss the rules of brainstorming:
Be spontaneous. Call out ideas as fast as they occur.
Absolutely no criticism, analysis, or evaluation of any kind is permitted while the ideas are being generated. Any idea may be useful, if only to spark another idea.
Emphasize quantity of ideas, not necessarily quality.

46. JRP reduces the amount of time required to develop systems
Benefits of JRP
JRP actively involves users and management in the development project (encouraging them to take “ownership” in the project)
JRP reduces the amount of time required to develop systems
When JRP incorporates prototyping as a means for confirming requirements and obtaining design approvals, the benefits of prototyping are realized
Teaching Tips
Discuss the reasons why JRP reduces the amount of time required to develop systems.

47. A Fact-Finding Strategy
Learn all you can from existing documents, forms, reports, and files
If appropriate, observe the system in action
Given all the facts that you've already collected, design and distribute questionnaires to clear up things you don't fully understand
Conduct your interviews (or group work sessions)
(Optional). Build discovery prototypes for any functional requirements that are not understood or if requirements need to be validated
Follow up
Teaching Notes
An analyst needs an organized method for collecting facts. An inexperienced analyst will frequently jump right into interviews. ``Go to the people. That's where the real facts are!'' Wrong! This attitude fails to recognize an important fact of life: people must complete their day-to-day jobs! Your job is not their main responsibility. Your demand on their time is their money lost.

48. Documenting Requirements Using Use Cases
A use case is a behaviorally related sequence of steps (a scenario), both automated and manual for the purpose of completing a single business task.
An actor represents anything that needs to interact with the system to exchange information. An actor is a user, a role, which could be an external system as well as a person.
A temporal event is a system event that is triggered by time.
Teaching Notes
Use cases describe the system functions from the perspective of external users and in the manner and terminology in which they understand. They are the results of decomposing the scope of system functionality into many smaller statements of system functionality.
An actor initiates system activity, a use case, for the purpose of completing some business task. An actor represents a role fulfilled by a user interacting with the system and is not meant to portray a single individual or job title.
Teaching Tips
Discuss with the students examples of use cases including temporal events.

49. Benefits of Using Use Cases
Facilitates user involvement.
A view of the desired system’s functionality from an external person’s viewpoint.
An effective tool for validating requirements.
An effective communication tool.
Teaching Notes
In order for use cases to be successful, participation by the user is imperative.

50. Example of a High-Level Use Case
Author: S. Shepard Date: 03/01/200
Use Case Name: New Member Order
Actors: Member
Description: This use case describes the process of a member submitting an order for SoundStage products. On completion, the member will be sent a notification that the order was accepted.
No additional notes.

51. Example of a Requirements Use Case
Author: S. Shepard Date: 10/05/200
Use Case Name: Submit New Member Order
Actor(s): Member
Description: This use case describes the process of a member submitting an order for SoundStage products. On completion, the member will be sent a notification that the order was accepted.
References: MSS-1.0
Typical Course of Events: 1
Actor Action
Step 1: This use case is initiated when a member submits an order to be processed
Step 7: This use case concludes when the member receives the order confirmation notice.
System response
Step 2: The member’s personal information such as address is validated against what is currently recorded in member services.
Step 3: The member’s credit status is checked with Accounts Receivable to make sure no payments are outstanding.
Step 4: For each product being ordered, validate the product number and then check the availability in inventory and record the ordered product information.
Step 5: Create a picking ticket for the member order containing all ordered products that are available and route it to the warehouse for processing.
Step 6: Generate an order confirmation notice indicating the status of the order and send it to the member. 2
Teaching Notes
 1. A reference to the requirement(s) in which it can be traced to.
 2. A typical event course describing the use case’s major steps, from beginning to end of this interaction with the actor.
 3. Alternate courses describing exceptions to the typical course of events.
4. Precondition describing the state the system is in before the use case is executed.
 5. Postcondition describing the state the system is in after the use case is executed.
 6. An assumptions section, which includes any nonbehavioral issues, such as performance or security, that is associated with the use case, but is difficult to model within the use case’s course of events.

52. Example of a Requirements Use Case (concluded)
Alternate Step 2: If the club member has indicated an address or telephone number change on the Courses: promotion order, update the club member’s record with the new information.
Step 3: If Accounts Receivable returns a credit status that the customer is in arrears, send an order rejection notice to the member.
Step 4: If the product number is not valid, send a notification to the member requesting them to submit a valid product number. If the product being ordered is not available, record the ordered product information and mark as “back-ordered.”
Pre-condition: Orders can only be submitted by members.
Post-condition: Member order has been recorded and the picking ticket has been routed to the warehouse.
Assumptions: None at this time. 3 4 5
Teaching Notes
 1. A reference to the requirement(s) in which it can be traced to.
 2. A typical event course describing the use case’s major steps, from beginning to end of this interaction with the actor.
 3. Alternate courses describing exceptions to the typical course of events.
4. Precondition describing the state the system is in before the use case is executed.
 5. Postcondition describing the state the system is in after the use case is executed.
 6. An assumptions section, which includes any nonbehavioral issues, such as performance or security, that is associated with the use case, but is difficult to model within the use case’s course of events. 6

53. Requirements Tables
Requirements traceability is the ability to trace a system function or feature back to the requirement that mandates it.
Requirement
Explanation
Requirement number:
Indicate a unique number or identifier of the requirement
Requirement title:
Assign short phrase indicating nature of the requirement
Requirement text:
Provide a textual statement of the requirement
Require
ment type:
Indicate the requirement type
Requirement details and
constraints
Functional characteristics or dimensions
Rev date and rev #:
Indicate the acceptance date and revision number of current
(accepted/baselined) version
Criticality
Must, Want, or Optional
Teaching Notes
Requirements tables can be very valuable if a requirement changes and you need to evaluate what impact that change may have on other requirements. By documenting requirements in this manner, related and dependent requirements can be grouped together or queried to make the systems analyst job easier. Other benefits to this style of documentation include it facilitates the prioritization of requirements by being able to specify the criticality of the requirement. It facilitates the tracking of changes of requirements and it provides a checkoff list when users are ready to accept the finished system to make sure all their needs were met.

54. Partial List of Member Services System Requirements
Explanation
Requirement number:
MSS -
1.0
Requirement title:
Process New Member Order
Requirement text:
The system should be able to process new member orders. Within this process it
should be able to validate member demographic information, verify credit
worthiness, inquire and modify inventory levels based on quantity of product
ordered, initiate backorder process in the event of insufficient inventory to fulfill
order, and send an order confirmation notice once the order has been placed.
Requirement type:
Functional
Requirement details and
Member credit status will be obtained from the Account Receivable system. A
constraints
picking ticket, containing the available ordered items, must be generated and
routed to the warehouse.
Rev date and rev#:
Version 1.0
Criticality
Must
Requirement
Explanation
Requirement number:
Teaching Notes
Example of documenting requirements using a table.
MSS -
Requirement title:
One Hour Order Confirmation Notice
Requirement text:
An notice must be generated and sent to the member, within one hour
from the time the member placed the order.
Requirement type:
Performance
Requirement details and
The member’s address must be stored on the system within the member’s
constraints
profile. The one- hour constraint applies only to the sending of the notification
And not when it’s received by the member. Related requirement(s): MSS-1.0
Rev date and rev #:
Version 1.0
Criticality
Must

55. System Architect Requirement Example
Teaching Notes
Example of documenting requirements using a case tool such as System Architect.