Relevant considerations:

A consistent system allows users to build mental models that will aid in the interaction and in the operation of the application. If consistency is missing, users have to rely more heavily on memorization instead of building and relying on mental models. When a user has a mental model of how the application performs the task, it will be easier for the user to perform his or her task.

A consistent system is easier to learn and use. To achieve consistency it is important that the development team of the application specify a set of conventions to be used during the development of the product. In the analysis phase it is therefore important to keep your eyes open for conventions followed in the present environment that can be moved into the new environment.

Here are some things that can help keep the interface consistent:

• Make information follow conventional standards as much as possible. For instance, use conventional English punctuation whenever possible and use both upper and lower case for the text. When displaying long numeric fields, use conventional punctuation schemas if they exist, punctuated with spaces, commas, hyphens, slashes, or whatever is most appropriate.

  Lists of alphabetic data should be left-justified and numeric data should use decimal alignment, so that data without decimals are right-justified.

• Each screen should have a heading that defines its contents.

• Label each data field to identify it for the user, thus reducing the memorization and providing for recall. Position the labels consistently, e.g. above columns and to the left of fields. Make the labels so they are easy to distinguish from the data. It may also be desirable to separate or partition groups of related data with blank spaces or any other means of separation.

• When expecting user input use one convention to prompt the user. Make it clear what actions are expected of the user.