Lrt System

USABILITY GOALS AND COMPETITIVE ANALYSIS

4.1 Objectives

Usability goal is an objective to measure the usability of the system. Usability goals are to help in delivering a usable system to its users.

There are various usability goals that can be developed for every system, where some of these usability goals can be detected before the proposed system is being developed.

Using the Delta method in the design and analysis phase during development, it will be able to confirm that the system is developed with high usability. Delta method is mainly focused on design and analysis phase rather than the implementation phase in the development process.

Input Activities Output

* Scenarios* Design Recommendations* User Profiling* Activity Graphs* System Vision* Guidelines * Develop test tasks* Set usability goals & requirements * Usability Specifications* Test Specification

The figure above shows the process of usability goals setting and requirement in Delta method, the Usability requirement setting.

Source: Adapted from http://www.deltamethod.net/7SettingUsabilityReq_index.htm

4.2 Setting Usability Goals

There are five main categories of usability goals, which are:-

* Learnability

* Efficiency

* Memorability

* Error

* Satisfaction

Learnability

Learnability is a way to measure learning aspects of usability, both initial learning and long-term learning and re-learning. A system which is easy to use/learn will be considered as a good system, and an easy to use/learn system is a system with an interface which is easy to learn allows users to build on their knowledge without deliberate effort.

Efficiency

Efficiency is a way to measure aspects of usability in terms of how fast and easily the tasks can be performed on the system, and information can be found and used from user documentation. When the user is able to learn the system easily, the ability for the users to do their work will be more efficient which will save time in their work.

Memorability

Memorability is the ability of the users on remembering how to use the ticketing machine once they have not been using for some time.

Errors

The ultimate goal to develop a system is a system which has no errors. But, product developers are human, and computer systems far from perfect, so errors may occur. An error tolerant program is designed to prevent errors caused by the user's interaction, and to help the user in recovering from any errors that do occur. When the system presents an error message to users, it gives enough information for them to be able to continue with their work. Better yet, the system helps to prevent errors.

Satisfaction

Satisfaction measures the freedom from discomfort, and positive attitudes towards the use of the product. Satisfaction can be specified and measured by subjective rating on scales such as discomfort experienced, liking for the system, satisfaction with system used, or acceptability of the workload when carrying out different tasks, or the extent to which particular usability objectives such as efficiency or learnability have been met. Other measures of satisfaction might include the number of positive and negative comments recorded during use.

4.3 Usability Accomplishment

Each goal should be accompanied by a requirement of how it is to be measured and which result is required to be considered as fulfilled. A goal can have more than one corresponding requirement. For instance, a high level goal that says that the system should be "easy to use" could have corresponding requirements both regarding efficiency and attitude (Design Technologies, 2005).

Learnability

A system which is easy to use/learn will be considered or perceived as a good system, which is what the proposed system intend to have. The evaluation and measurement of the time users has perform on a certain task is unable to be carried out, due to the functionality of the system is not available.

Therefore, testing on how a user used the original bus ticketing machine is being carried out under this goal. It is found that the user learns to use the ticketing machine very fast. The results retrieved from the users who used the ticketing machine were very pleased. As a result, it is found that the users are able to adapt to the system very quickly and are able to navigate the ticketing machine throughout the entire process.

Memorability

Memorability is the ability of the users on remembering how to use the ticketing machine once they have not been using for some time. Again, it is unable to test on the users as the ticketing machine is not fully functioning. Therefore, the users who have done the testing for learnability is asked to carried out the task on the ticketing machine again to prove the achievement of this goal. The testing on the ticketing machine performed by the user was timed and reached a satisfactory level where it indicates that user has a memory of what had been done or need to be done to achieve the end result, which is to purchase the bus ticket.

Efficiency

When a user is able to use/learn the system easily, then the ability for users to perform a task (purchasing a bus ticket) will be more efficient which will save time in the task done. As it is mentioned before, the functionality of the system is unavailable because only the design of the bus ticketing machine is being developed. Due to the data involvement on the bus ticketing machine is minimal, the process to perform a task efficiently (purchasing a bus ticketing machine) is high.

4.4 Critical Evaluation on Usability Goals

The evaluation on usability goals needed to fulfil 5Es which are Effective, Efficient, Engaging, Error Tolerant, Easy to Learn. All of these are affected by the User Interface navigation