1. Chapter 4 Design Approaches and Methods
No agreed standards on design practice.
Different schools of thought, e.g. one school suggested that design should follow formal scientific and engineering practices, whilst another school argues that design should incorporate a strong creative element.

2. Since we deal with user interaction, we will focus on User-centered Design.
Even within the HCI community, there are a number of different schools of thought in terms of how user centered design should be done.
However, they all agree on a number of things.

3. What HCI schools agree on in terms of user centered design:
1) the design should involve users as much as possible and let them influence the design.
2) the design should integrate knowledge from various different sub-disciplines of HCI.
3) the design process should be continuously evaluated to make sure the design is effective.

4. Design Approaches: Grouping
Graphic design basics
Alternative system development processes (e.g. waterfall model, participatory design), life cycle model, iterative design, choice of method under time/resource constraint
Task analysis techniques
Design specification techniques
Industrial design basics
Design case studies and empirical analyses of design

5. Waterfall model of the life cycle
In the Waterfall model, the software process is seen as consisting of a number of stages.
After each stage, the progression of the product is checked by the process of validation (“does it fulfil user expectations”) and whether it correctly represents the previous stage (verification).

6. Waterfall model Analysis of requirements
Different boxes representdistinct phases of software life cycle
System and software design
Implementation and unit testing
Integration and system testing

7. Iteration in the Waterfall model
In reality, there is a great overlap between phases of the software life cycle (arrows represent overlap between phases (=boxes))
Analysis of requirements
System and software design
Implementation and unit testing
Integration and system testing

8. Waterfall model of the life cycle continued
Difficulty with this sort of system:
1) both customer and user will have little idea how the final outcome of the system will exactly look like (due to a number of modification between the phases in the software life cycle).

9. Waterfall model of the life cycle continued
Difficulty with this sort of system:
2) It is difficult, very expensive and also very time consuming to make changes to these systems once they have already been implemented.
3) Therefore, it would be best if users are given a realistic impression about the final outcome of the system at an early stage, but this is difficult to achieve.

10. Waterfall model of the life cycle continued
Difficulty with this sort of system:
4) The biggest problem is that it is impossible to completely understand the requirements of the users until the project has already proceeded to a certain stage of development (i.e. a lot of design has to take place before one can judge what might be best for the users and this design may be a waste of effort because it may be useless).

11. What is the alternative?
Prototyping...
...allows to create models of the systems quickly and efficiently. The designed models can be tested by users, who are welcome to make suggestions in terms of what they would change.
...let users perform some tasks and let them think aloud what they are doing (this often leads to many suggestions for improvement).

12. Principles of user centered design
It is important to consider the design from the perspective of the user rather than from the system perspective.
The purpose is to have systems that are easy to learn and use, as well as safe and effective in allowing the activities that people want to do.

13. Principles of user centered design continued
Consider what is best for the user, and this is rarely something that is the easiest for the system designer to implement or program.
In order to find out what is best for the user, the first and most important point is to get to know the user.

14. Principles of user centered design continued
How can one achieve the goal to get to know the users?
One can perform techniques such as user analysis, task analysis, information flow analysis etc.
Gould et al. (1987) also make very important suggestions.

15. Gould et al. (1987): Principles of user-centered design
1. To focus on the users and their tasks very early on in the design process. This includes user guides and manuals, help options and making sure that the users’ cognitive, social and attitudinal characteristics are well understood and considered in the process of design.

16. Gould et al. (1987): Principles of user-centered design continued
2. To make use of prototype manuals, prototype interfaces and other models/simulations of the system.
3. Taking an iterative design process (no matter how good or experienced the designer, s/he never gets it right from the beginning)

17. Gould et al. (1987): Principles of user-centered design continued
4. All factors of usability should evolve together and be supervised by one particular group that has an overview over all the stages of development (for an explanation of usability see pages 1 to 4 in the study guide or first lecture “Introduction”).

18. SUMMARY: Principles of user-centered design
User-centered systems typically underlie a rapid and iterative (=many steps are carried out again and again until design is perfect) design process.
User-centered design focuses on users in the first place, as well as their work and environment. It considers how current technology can benefit the users in the best possible way and chooses design appropriately

19. SUMMARY: Principles of user-centered design continued
Apart from focusing on people, the particular characteristics of the system need to be considered as well.
There are many different software systems of varying size, complexity, constraints, purpose and cost. This all has a substantial influence on the design process.

20. Additional remarks: Principles of user-centered design continued
If the product is particularly designed for one company, the users of the final product within the company should be involved in the design process. This can be a highly specialised product that is taylored to the needs of the specific users.

21. Addional remarks: Principles of user-centered design continued
If a generic system is designed that has many users in mind and will be sold on the open market, general information about user characteristics should be considered and the product that suites the majority of users best will be the most likely to be chosen. So it depends on the context what the system is for.