Design Guidelines, Principles and Theories.md

Design Guidelines, Principles and Theories

tags: UI

Basic Definitions

• Guidelines: Low-level general advice about the best and bad practices
• Principles: Middle-level rules and strategies for how things should be done
• Theories: High-level frameworks about how user experiences

HCI Theories

How does theories help?

• Guide researchers in understanding relationships between concepts and generalizing results.
• Power of theories to shape design
  • Guide practitioners in making design tradeoffs for products.
  • Guide practitioners in designing new products, while helping to refine existing ones.

HCI Theories can be split into Micro and Macro theories.

Out of which they could also categorized into:

• by Theory Type
  • Descriptive: describe user interfaces and their uses with consistent terminology and taxonomies (classifying complex set of phenomena into understandable categories)
  • Explanatory: Describe sequences of events with causal relationships
  • Prescriptive: Offers guidelines for designers to make decisions
  • Predictive: Enable comparison of design alternatives based on numeric predictions of speed/errors.
• by Human Capacity
  • Motor: Pointing, clicking, dragging, forms of direct manipulation by the user
  • Perceptual: Visual, auditory, tactile etc
  • Cognitive: Problem Solving with ST/LT memory

Micro Theories

Micro theories focus on measurable performances on standard tasks in terms of seconds/minutes in laboratory environments.

There are 3 types of micro theories.

1. Design-by-levels
   • Start with high level design and move to smaller objects and actions
2. Stages-of-Action
   • Consider user behavior as they form intentions and seek to achieve their goals
   • Explained here
3. Consistency
   • Consistency in objects and actions, shown by words, icons, colors, shapes, gestures and menu choices
   • Gives rise to the concept of design systems.

Design-by-levels Theories

4-level design-by-levels theory format

1. Conceptual level: Mental Model
2. Semantic level: Meanings conveyed from the interaction of the user's input and the computer's output display
3. Syntactic level: How tasks are defined and achieved through user actions that convey semantics
4. Lexical level: hardware dependencies and precise mechanisms

GOMS Approach

Goals ➡️ Operators ➡️ Methods ➡️ Selection Rules

1. Decompose goals into many operators (actions)
2. Decompose operators into methods
3. User apply selection rules to choose among the various methods for achieving goals.

Macro Theories

There are 2 main types of macro theories, which can be easily understood and categorized in terms of time ⌚

1. Contextual: Past + Present
   • Highly dependent on various circumstances and experiences of the user such as the technical, economical, cultural, social, emotional, physical etc.
2. Dynamic: Present + Future
   • Takes into account that the user can GROW in terms of the goals that they want to achieve, which lead to changes to the tasks they want to perform and have to perform
     • interesting tasks for users can be encouraged by the UI, perhaps with gamification or sth else
     • necessary tasks are imposed by the UI
     • with more familiarity with the UI, users will gain confidence and have a greater sense of responsibility for quality