Lesson 04: Interface Design

Lesson Objectives

Good interface design has significant positive results. High-quality design is a process which requires knowledge of systems design processes and user characteristics, such as users' physical characteristics, limitations, and motivations. Interfaces should be designed with simple, balanced, and consistent screens.

After reading this lesson, you should be able to:

• Describe approaches to interface design.
• Identify types of interfaces.
• Describe the process of iterative design and prototyping.

Interface Design

Many information technology interfaces are poorly designed. Many people are not able to use interfaces effectively due to poor design. Good interface design is important for reducing costs, errors, additional training, and employee turnover; and increasing user satisfaction, productivity, and quality products and services.

Good interface design requires diverse knowledge of systems design processes and user characteristics, including:

• Users' physical characteristics, limitations, and disabilities.
• Speed and efficiency needs.
• Reliability issues.
• Security concerns.
• Level of usability and functionality required.
• Frequency of product use.
• Users' past experience with same or similar product.
• Level of cognitive or mental effort required from the user.
• Users' tolerance for error.
• Users' patience and motivation for learning.
• Cultural and language aspects.

Good Interface Design

Good interface design requires diverse knowledge of systems design processes and user characteristics, including:

• Users' physical characteristics, limitations, and disabilities: Interface designers need to understand the characteristics of their users. For example, an Automatic Teller Machine (ATM) interface must be accessible by elderly, young, and disabled bank customers.
• Speed and efficiency needs: Many interfaces need to be quickly accessible and effective. For example, military pilots must have cockpit interfaces that allow quick and efficient interaction.
• Reliability issues: Interfaces that affect human lives need to provide reliable and readable information. For example, if an interface is provided information in a nuclear power plant system or a hospital operating room, the data quality and presentation needs to be accurate and reliable.
• Security concerns: Interfaces must have effective security and access mechanisms as required by an organization. For example, a bank Automatic Teller Machine (ATM) must allow bank customers to securely access their accounts and also keep out potential hackers.
• Level of usability and functionality required: Interfaces for users with little computing experience are more simply structured than interfaces designed for expert level users. For example, many interfaces offer advanced options and features for more expert users.
• Frequency of product use - Interfaces in high use computer systems need to be more reliable and effective to cater for fast interaction and a variety of users. For example, a bank Automatic Teller Machine (ATM) is used by hundreds of customers every day. The interface must allow for quick and effective interaction.
• Users' past experience with same or similar product - Many interfaces and systems provide similar features. For example, many bank Automatic Teller Machines (ATMs) provide identical functions and use similar banking terminology. The concepts of "withdrawal" and "deposit" that appear on ATM interfaces are familiar to bank users.
• Level of cognitive or mental effort required from the user - Many complex computer packages require a high level of financial or accounting knowledge. For example, the interface to the Quicken software requires knowledge of financial practices and accounting methods.
• Users' tolerance for error - Many interfaces allow users to complete actions with serious consequences when errors occur. For example, in a hospital emergency room, the medical computer interfaces need to be accurate, reliable, and without error, or patients may die.
• Users' patience and motivation for learning - Many interfaces are designed to allow users effective interaction with little learning required. For example, bank Automatic Teller Machines (ATMs) are simple menu systems that are designed to allow quick and easy learning.
• Cultural and language aspects - Interface designers must take account of users' cultural and language differences. For example, many interfaces that are designed for users in the multicultural United States society provide interaction in English, Spanish, Chinese, or other languages.

Scenario

One example of an interface redesign is from case study done at a fitness center with a touch screen interface on a Fitness Track machine. The usability problems included the button size was too small, the font size was too small, and multiple screen touches were entered by accident. These issues were resolved by observing the usability problems and creating solutions that addressed the problems. The users' physical characteristics and limitations had not been considered in the original design. This interface should have been designed with non-technology users' limitations in mind. To solve the problems, button size was increased, font size was increased, and a delay was added to the response of the button, so that repetitive touches of the screen were treated as one touch of the screen. The interface design was also simplified. These solutions enhanced the usefulness of the Fitness Track machine.*

*Stumpfhauser, L. & Chaparro, B. (2001). Designing a touch screen kiosk for older adults: a case study. Retrieved on August 12, 2003 from http://psychology.wichita.edu/ surl/usabilitynews/3W/kiosk.htm

User Centered Design

User centered participatory design involves the inclusion of users input into each phase of the user centered design process, including the user walkthrough and approval of each interface feature of a systems prototype.

User centered design involves the identification and consideration of relevant human factors in the design, evaluation, and implementation of information technology interfaces.

Displays should be readable (consider size, position, and ambient lighting) with differentiate and consistent displays (by shape, color, position, and size) that are compatible with the task to be performed.

HCI Design Process

The steps in the HCI design process can include the following steps:

1. Analyzing the users and determining their needs.
2. Drafting an initial design based on the users' needs analysis.
3. Testing the initial design with users in an HCI testing laboratory or in a real user work environment.
4. Developing a prototype system based on the initial design and users' feedback.
5. Testing the prototype system with users in an HCI testing laboratory or real user work environment.
6. Designing and refining each specific interface and screen.
7. Testing the interface with users in an HCI testing laboratory or a real user work environment.
8. Refining the interface based on users' feedback.
9. Implementing the interface.

Lesson Wrap-Up

As you now know, there are specific steps and tasks that a HCI worker would do in the process of completing a user centered participatory design. Do not forget about providing system updates and maintenance to the design. Sensitivity to user characteristics, including disabilities, is important in making your interface accessible by all users.

Now that you have completed this lesson, you should be able to:

• Describe approaches to interface design.
• Identify types of interfaces.
• Describe the process of iterative design and prototyping.

Additional User Interface Design Reading:

Schneiderman, B. (1998). Designing the user interface: Strategies for effective human computer interaction. Reading: Addison Wesley Longman.

Discussion Activity Assignment

Conduct a real-world observation of people using a system such as an ATM machine, Lion Cash machine, or Swipe card machine for doors. Write a report describing the system. Make sure to include a description of the interface, the functions of the system, the social environment of system, and your observations of people using the system. Also include at least one picture of the interface. Observe for 30 minutes, but do not talk to the users. You should only make observations. Be sure not to jeopardize users' security by observing too closely. Post your reaction below as a comment.