Human Computer Interaction (HCI):Chapter-7-a- Design Rules

Summary

This lecture delves into the concept of usability in software design, emphasizing the importance of following design rules to create user-friendly software. The transcript covers three types of design rules: principles (abstract and flexible), standards (specific and authoritative), and guidelines (advisory and general). The speaker explains how rules vary in authority and generality, guiding designers to balance usability and compliance. Additionally, the lecture touches on the significance of reusing design patterns and resolving conflicts with clear justifications. The session concludes with a preview of key usability frameworks, including Nielsen's 10 heuristics and Shneiderman’s 8 golden rules.

Takeaways

• 😀 Usability is the primary goal of software design, ensuring that the software meets user needs and provides an enjoyable experience.
• 😀 Design rules are guidelines that increase the usability of software, helping it perform all necessary actions and fulfill user requirements.
• 😀 Design rules can be categorized based on authority (mandatory vs. optional) and generality (broad vs. specific).
• 😀 Rules with high authority, such as standards, must be followed to ensure compliance, while low-authority rules, like guidelines, are optional.
• 😀 General rules can be applied to various design scenarios, while specific rules cater to particular technologies or problems.
• 😀 Principles are abstract design rules with low authority and high generality, providing guidance but not mandating their implementation.
• 😀 Standards are specific rules for particular domains or technologies, carrying high authority and requiring compliance to meet industry expectations.
• 😀 Guidelines are advice or recommendations that are low in authority but help improve design quality when no standards are in place.
• 😀 A balanced approach using both standards (high authority) and guidelines (low authority) helps create more usable and standardized software.
• 😀 ISO 9241 defines usability as effectiveness, efficiency, and satisfaction with which users accomplish their goals in a specific environment.
• 😀 Reusability of design patterns and knowledge across projects helps save time and effort, avoiding the need to recreate successful designs.

Q & A

What is the primary goal of software design discussed in the transcript?

The primary goal of software design discussed is usability, ensuring that the software is usable, meets user requirements, and provides a positive experience for the user.

How are design rules categorized in the script?

Design rules are categorized by two dimensions: authority and generality. Authority refers to whether the rule must be followed strictly or is just a suggestion, while generality refers to how widely the rule can be applied across different design situations.

What is the difference between principles and standards in software design?

Principles are abstract design rules that are low in authority and more general in application, meaning they are optional. Standards, on the other hand, are specific, authoritative rules that must be followed to ensure compliance, particularly in regulated or specialized domains.

Why are guidelines considered to have low authority in design rules?

Guidelines are considered to have low authority because they are not mandatory but provide advice or suggestions to help improve design. They guide designers without compelling them to follow them strictly.

What is the role of standards in usability and design?

Standards play a critical role in ensuring that the software meets specific usability requirements and functions as expected within defined parameters. They are set by recognized authorities and are mandatory to ensure compliance with industry norms.

What are the three components of usability as defined by ISO 9241?

The three components of usability defined by ISO 9241 are effectiveness, efficiency, and satisfaction. These ensure that the user can complete tasks accurately and comfortably, with minimal resources expended.

How do principles help in software design?

Principles help in software design by offering abstract guidance and direction for designers, although they are not mandatory. They provide high-level recommendations that help ensure the software meets user needs, even if they are not always applied in every situation.

What does the concept of 'generality' mean in design rules?

Generality refers to how broadly a design rule can be applied to different types of design situations. A rule with high generality can be applied to many design contexts, whereas a rule with low generality is more specific to particular cases or domains.

What is the significance of reusing design knowledge or patterns in software development?

Reusing design knowledge or patterns is significant because it saves time and effort by avoiding the need to 'reinvent the wheel.' It allows developers to leverage solutions that have already been proven to work in similar contexts.

What challenges are mentioned regarding the authority of design rules?

A challenge mentioned is that many design rules for interactive systems are not authoritative but are instead suggestive or general guidelines. This is due to incomplete theories or the evolving nature of technology, which makes it difficult to create specific, authoritative standards for every aspect of design.