Use cases – definition of requirements and goal-settings of developing products

When is this method appropriate?

Use cases describe the usage procedure of single target-groups who perform them with the aid of the application or website to gain a particular goal.

In the use case specification the use cases are explicitly listed with all steps of the person-machine-interaction. By this the complete system functionality is general comprehensible determined. This is necessary so that use cases are equally understood from the functional and technical site.

Due to the identified goal-settings and requirements of the users necessary functions and contents for the developing website and application can be derivated.

Therewith use cases form besides personas or a clear definition of the target-group (for instance user structure analysis by an onsite survey within a re-design) a base for a successfully development process.

Possible questions

• How do my (potential) users act with the website/application?
• What requirements arise due to the goal-settings of single users to the needed contents and functions?
• How can particular interaction processes or tasks be implemented with reference to the number of process steps and their order among them?
• How can single tasks be prioritised among each other? What are the central interaction processes?

And many more…

In what project phase applicable?

At the beginning of the development process defined use cases are definitely not “written in stone”. It is more a kind of dynamic documentation that is continual tested, modified and extended within the whole development process.

• Analysis
  At the beginning of the development process the typical goal-settings/use procedures are analysed and documented. They form the necessary base for the design of the contents and functions of an website/application.
• Development/conception
  In the early conception phase the use cases that were created in the analysis phase serve as master for the task scenarios for the testing of earlier prototypes (rapid prototyping).
• Programming/implementation
  On the base of the use cases e. g. the current status can be aligned with the defined goal-settings at the beginning within a final usability test in laboratory in sense of quality management.

What is the procedure of this method?

To create use cases one needs to know the target-group(s) – their intentions, requirements and expectations with reference to the developing product. Therefore so-called personas or a requirement analysis with Kano put themselves forward.

On this basis the actions and interactions steps that are necessary for particular tasks are defined by usability experts in a use case workshop.

This refers to the number of single needed steps as well as for their order. Of course, it is continual tested whether the user is later able to recognise the action steps and the availability of the next action step.

Finally, the form of the single use cases in modular and simple comprehensible, narrative texts takes place.

In the next step it is important to prioritise the defined use cases. Then the website/application can be aligned to the central use cases.

During the creation of the use cases no actual users are needed. But it is necessary to ascertain comprehensive data beforehand. This can take place with the following methods & procedures for instance:

• Requirement analysis with Kano
• Focus groups
• Onsite survey
• Panel survey
• Personas
• In-depth interviews
• Usability test in laboratory

Strengths of this method

• Use cases are the base to show what procedures should be prioritised.
• They enable to comprehensively describe the functional und contentual requirements of a website/application.
• They simplify to keep in sight the goal-settings during the development process.
• Use cases serve as an efficient instrument to come to an understanding between the single project partners.
• They minimise the risk of misunderstandings and very different expectations.
• Use cases are the base for scenarios in user tests.
• They enable to align the current status (actual figure) with the goal-settings that were defined at the beginning (intended figure) in sense of quality management.

What about the sample size?

The definition of the single use cases on the base of the previous ascertained user data takes place without test subjects. Generally, two usability and interaction experts (with long term experience in their branch) occupy with the definition and the final arrangement of the use cases within a use case workshop.

How much time takes the implementation?

The effort for the fixation appeals exclusively to the complexity of the developing website/application or its genre. Less complex websites/applications (referred to the number of possible or planned functions and contents) can be provided from 3 to 5 days (modelled uses cases incl. a prioritisation).

What input do you have to provide?

Optimally comprehensive data about your target-group(s) already exist for instance in terms of personas or a user structure analysis (onsite survey ), that we can use for the definition of the use cases for your website/application.

On demand we support you during the ascertainment of the end-user data. Thereby we draw on our comprehensive project experiences in the fields of requirement and user structure analysis.

What do you receive from us?

All central interactions are described in use cases and modular written as a simple and understandable, narrative text.

A use case contains inter alia:

• The single action steps.
• The concrete goal-setting.
• The master context and the relation to the other described use cases (interaction effects).
• Possible preconditions for particular actions.
• The trigger for the use case.
• The events that lead to a successful deal or to possible failure of interactions.

Do you have any further questions? Please do not hesitate to contact us! We would like to consult you.