The main goal of HCI is to produce usable, safety and functional System for the user. To accomplish this developer must
- Understand how user going to use the System.
- Develop suitable tools and techniques to the System.
- Achieve efficient, effective and safe interaction between user and system.
- always put users first
In order to achieve this goal of HCI, we need to achieve two major sub-goals. (Usability goal and User Experience goal)
Usability is one of the key concepts in HCI which concerns with making system easy to learn and use. A usable System must
- Easy to Learn
- Easy to remember (How to use)
- Effective to use
- Efficient to use
- Safe to use
- Enjoyable to use
Why is usability important?
A system built with less regard to usability leads to frustration, waste of time and errors.
Usability can be broken down into the following goals.
Effectiveness – It refers to how good a system, at doing what it is supposed to do.
Efficiency – How much a system supports the user to carry out his tasks.
Safety – Protecting users from dangerous conditions and undesirable situations. There are two types of dangerous conditions.
- External Conditions – Conditions that can cause danger to users physically, or simply can be told as ergonomic factors
- Internal Conditions – Conditions which are triggered by unwanted accidental actions of a user. Users always fear about making mistakes and errors and how they will affect the System and lead to severe consequences. To protect users from such conditions,
- preventing the user from activating wrong keys and buttons mistakenly
- providing users various means of recovery for the mistakes they could make, this will make the user feel confidence and allow the user to explore the interface of the system.
Utility – It refers to the right functionalities, a system providing to the user to accomplish the intended task. An example of a system with the high utility is an IDE (Integrated Development Environment) which provides various suggestions and tools to a programmer, and a system with the low utility is a simple text editor which forces the user to do most of the works while programming.
Learnability – It is about how much a system is easy to learn for a new user, people wish to become familiar with the system easily rather than spending more time on learning the system. For example, modern OS (Operating Systems) with GUI is easy to learn compared to the older DOS operating system with CLI.
Memorability – Refers to how easy a system to be remembered. It is important for the Interactive systems that are used infrequently.
User Experience Goal
User experience is about the subjective qualities of that determines how the user feel about a particular system. It is a study on user feelings to increase the positive feeling of a user while using the system.
Desirable aspects – Satisfying, helpful, fun, Enjoyable, motivating and Surprising.
Undesirable aspects – Boring, unpleasant, frustrating and annoying.
University of Jaffna