Requirement Gathering and their types

Requirement Gathering and their types 

1)     One-on-one interviews

The most common technique for gathering requirements is to sit down with the clients and ask them what they need. The discussion should be planned out ahead of time based on the type of requirements you're looking for. There are many good ways to plan the interview, but generally you want to ask open-ended questions to get the interviewee to start talking and then ask probing questions to uncover requirements.

2)     Group interviews

Group interviews are similar to the one-on-one interview, except that more than one person is being interviewed — usually two to four. These interviews work well when everyone is at the same level or has the same role. Group interviews require more preparation and more formality to get the information you want from all the participants. You can uncover a richer set of requirements in a shorter period of time if you can keep the group focused.

3)    Facilitated sessions

In a facilitated session, you bring a larger group (five or more) together for a common purpose. In this case, you are trying to gather a set of common requirements from the group in a faster manner than if you were to interview each of them separately.

4)     Joint application development (JAD)

JAD sessions are similar to general facilitated sessions. However, the group typically stays in the session until the session objectives are completed. For a requirements JAD session, the participants stay in session until a complete set of requirements is documented and agreed to.

5)    Questionnaires

Questionnaires are much more informal, and they are good tools to gather requirements from stakeholders in remote locations or those who will have only minor input into the overall requirements. Questionnaires can also be used when you have to gather input from dozens, hundreds, or thousands of people.

6)    Prototyping

Prototyping is a relatively modern technique for gathering requirements. In this approach, you gather preliminary requirements that you use to build an initial version of the solution — a prototype. You show this to the client, who then gives you additional requirements. You change the application and cycle around with the client again. This repetitive process continues until the product meets the critical mass of business needs or for an agreed number of iterations.

7)    Use cases

Use cases are basically stories that describe how discrete processes work. The stories include people (actors) and describe how the solution works from a user perspective. Use cases may be easier for the users to articulate, although the use cases may need to be distilled later into the more specific detailed requirements.

8)    Following people around

This technique is especially helpful when gathering information on current processes. You may find, for instance, that some people have their work routine down to such a habit that they have a hard time explaining what they do or why. You may need to watch them perform their job before you can understand the entire picture. In some cases, you might also want to participate in the actual work process to get a hands-on feel for how the business function works today.

9)    Request for proposals (RFPs)

If you are a vendor, you may receive requirements through an RFP. This list of requirements is there for you to compare against your own capabilities to determine how close a match you are to the client's needs.

1           10)   Brainstorming

On some projects, the requirements are not "uncovered" as much as they are "discovered." In other words, the solution is brand new and needs to be created as a set of ideas that people can agree to. In this type of project, simple brainstorming may be the starting point. The appropriate subject matter experts get into a room and start creatively brainstorming what the solution might look like. After all the ideas are generated, the participants prioritize the ones they think are the best for this solution. The resulting consensus of best ideas is used for the initial requirements.

Example form for requirement gathering:

Here is some basic types of requirement are

Ø Architectural requirements

Ø Structural requirements

Ø Behavioural requirements

Ø Functional requirements

Ø Non-functional requirements

Ø Core functionality and ancillary functionality requirements

Ø Performance requirements

Ø Design requirements

Ø Derived requirements

Ø Allocated requirements

1.     Architectural requirements

Architectural requirements explain what has to be done by identifying the necessary systems architecture of a system

2.     Structural requirements

Structural requirements explain what has to be done by identifying the necessary structure of a system.

3.     Behavioral requirements

Behavioral requirements explain what has to be done by identifying the necessary behavior of a system.

4.     Functional requirements

Functional requirements explain what has to be done by identifying the necessary task, action or activity that must be accomplished. Functional requirements analysis will be used as the top level functions for functional analysis.

5.     Non-functional requirements

Non-functional requirements are requirements that specify criteria that can be used to judge the operation of a system, rather than specific behaviors.

6.     Core functionality and ancillary functionality requirements

 Core functionality requirements are those without fulfilling which the product cannot be useful at all. Ancillary functionality requirements are those that are supportive to core functionality

7.     Performance requirements

The extent to which a mission or function must be executed. Generally measured in terms of quantity, quality, coverage, timeliness or readiness.

8.     Design requirements

The "build to", "code to", and "buy to" requirements for products and "how to execute" requirements for processes expressed in technical data packages and technical manuals

9.     Derived requirements

Requirements that are implied or transformed from higher-level requirement. For example, a requirement for long range or high speed may result in a design requirement for low weight.

10.             Allocated requirements

A requirement that is established by dividing or otherwise allocating a high-level requirement into multiple lower-level requirements.