Complete – describe all possible system inputs and responses.
Feasible – can be satisfied based on the available resources and constraints.
Required – truly needed and fulfill the purpose of the system.
Accurate – stated correctly.
Traceable – directly map to functions and features of system.
Verifiable – defined so can be demonstrated during testing.
Process of Requirements Discovery
Problem discovery and analysis
Documenting and analyzing requirements
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.
Problem at right (fish head)
Possible causes drawn as "bones" off main backbone
Brainstorm for 3-6 main categories of possible causes
Given an understand of problems, the systems analyst can start to define requirements.
Fact-finding – the formal process of using research, meetings, interviews, questionnaires, sampling, and other techniques to collect information about system problems, requirements, and preferences. It is also called information gathering or data collection.
Determine the who, what, where, when, why, and how of the observation.
Obtain permission from appropriate supervisors.
Inform those who will be observed of the purpose of the observation.
Keep a low profile.
Review observation notes with appropriate individuals.
Don't interrupt the individuals at work.
Don't focus heavily on trivial activities.
Don't make assumptions.
Questionnaire – a special-purpose document that allows the analyst to collect information and opinions from respondents.
Free-format questionnaire – a questionnaire designed to 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 questionnaire – a questionnaire containing questions that require selecting an answer from predefined available responses.
Often can be answered quickly
People can complete at their convenience
Relatively inexpensive way to gather data from a large number
Is the current accounts receivable report that you receive useful? ___ Yes ___ No
Developing a Questionnaire
Determine what facts and opinions must be collected and from whom you should get them.
Based on the facts and opinions sought, 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.
Interview - a fact-finding technique whereby the systems analysts collect information from individuals through face-to-face interaction.
Get the end-user involved
Solicit ideas and opinions
The personal interview is generally recognized as the most important and most often used fact-finding technique.
Types of Interviews and Questions
Unstructured interview –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.
Structured interview –interviewer has a specific set of questions to ask of the interviewee.
Open-ended question – question that allows the interviewee to respond in any way.
Closed-ended question – a question that restricts answers to either specific choices or short, direct responses.
Give analyst opportunity to motivate interviewee to respond freely and openly
Allow analyst to probe for more feedback
Permit analyst to adapt or reword questions for each individual
Can observe nonverbal communication
Success highly dependent on analyst's human relations skills
May be impractical due to location of interviewees