Design Principles and Usability Heuristics

Design Principles are used in ‘the process of designing products so that they can be used by as many people as possible in as many situations as possible’.

Design principles and usability heuristics are both considered to be important guidelines for designing user-centered systems, and they are typically used in conjunction with task-centered system design (TCD) and other user-centered design methods. Design principles refer to general guidelines that can be used to design effective and usable systems. They are often based on research in cognitive psychology, human-computer interaction, and other related fields, and provide a broad framework for designing systems that meet the needs of users.

Universal design is primarily about trying to ensure that you do not exclude anyone through the design choices you make but, by giving thought to these issues, you will invariably make your design better for everyone.

Importance of Design Principles in User Experience Design

Design Principles are a set of guidelines that shape the overall design of a product, while usability heuristics provide specific evaluation criteria to ensure that the design meets the needs of the end-user. Both design principles and usability heuristics are critical in creating a positive user experience, as they ensure that the product is intuitive, efficient, and enjoyable to use. Design Principles provide a framework for designers to make design decisions and prioritize design elements based on the desired user experience. For example, the principle of "simplicity" emphasizes the importance of reducing clutter and minimizing distractions to make the product easier to use. Another example is the principle of "consistency," which ensures that the product's design elements, such as buttons, icons, and navigation, are consistent throughout the product to reduce confusion and enhance usability. Incorporating Design Principles into the design process helps ensure that the product meets the needs and expectations of the target user and delivers a positive user experience.

Types of Design Rules:

1. Principles 

• Abstract design rules
• Low authority
• High generality

2. Standards

• Specific design rules
• High authority
• Limited applications
• Set by national or international bodies to ensure compliance by a large community of designers
• Requires sound underlying theory and slowly changing technology
• Hardware standards are more common than software high authority and low-level detail
• ISO 9241 defines usability as effectiveness, efficiency, and satisfaction with which users accomplish tasks

3. Guidelines

• Lower authority
• More general application
• More suggestive and general
• Many textbooks and reports full of guidelines
• Abstract guidelines (principles) applicable to early cycle activities
• Detailed guidelines (style guides) applied to later lifecycle activities
• Understanding, the rationale for policy helps resolve conflicts

Design:

Simply defining design means achieving goals within constraints. This is not an all-encompassing design guide, but it helps focus on specific things such as goals, constraints, and trade-offs.

• For HCI, the obvious ingredients are humans and computers. That is, understanding computers - their limitations, capabilities, tools, platforms, and people - understanding their psychological, social aspects, and human error.
• The Design itself is a process that includes the following steps: requirements, analysis, design, iteration, and prototyping, implementation and deployment.

Design Principles:

• Design principles are guidelines, biases, and design considerations that designers wisely apply. Experts from many disciplines—e.g., behavioral science, sociology, physics, ergonomics—accumulated knowledge, and his experience provided the basis for design principles.
• Design principles are basic advice for creating user-friendly and attractive designs. A design principle is a set of values ​​that act as a compass for your product.
• Universal Design Principles (UDP) help UX designers create software that people of all abilities can use without having to change anything or use assistive technology. An approach to products and environments that are accessible and usable by as many users as possible without requiring additional customization or special design or redesign.
• In the context of human-computer interaction (HCI), design for all implies taking a proactive approach toward products and environments that would be accessible and usable by the broadest possible user population, without the need for additional adaptations or specialized design or redesign.
• The user interface should be simple, easy to use, and more importantly accessible to users of various skill levels. The HCI community believes that UX design should provide a great user experience and delight users.

In the late 1990s, a group at North Carolina State University, USA, proposed his seven general principles of universal design. These should cover all areas of design and are equally applicable to designing interactive systems. These principles provide a framework for developing the universal design.

• Equitable use
• Flexibility in use
• Simple and Intuitive to use
• Perceptible information
• Tolerance for error
• Low physical effort
• Size and space for approach and use 

1. Principle one is Ease of Use: It is a set of abilities and attractiveness to everyone. No users are excluded. Whenever possible, access should be equal for everyone. Where identical use is not possible, equivalent use should be encouraged. Safety, privacy, and security protections should be available to all as appropriate.

2. Principle two is Flexibility of Use: The design allows for different skills and preferences by choosing usage and adapting to the user's pace, precision, and habits.

3. Principle three is that the system is Simple and Intuitive to use, regardless of the user's level of knowledge, experience, language, or concentration. The design should support user expectations and take into account different languages ​​and reading comprehension. It should not be unnecessarily complicated and should be organized in a way that facilitates access to the most important areas. You should provide prompts and feedback whenever possible.

4. Principle four is Perceptible Information: The design should enable effective communication regardless of environmental conditions or user abilities. Redundancy in presentation is important. The information must be presented in various forms or modes (graphic, verbal, text, touch, etc.). Presentations must support the variety of devices and techniques that people with different sensory abilities use to access information.

5. Principle five is Tolerance for Error: Minimize the impact and damage caused by errors and unintended behavior. Potentially hazardous situations should be removed or made difficult to access. From the user's perspective, the system should be fail-safe and should support the user in tasks that require concentration.

6. Principle six is Low Physical Effort: Systems should be designed to be comfortable to use and to minimize physical strain and fatigue. The physical design of the system should allow the user to maintain a natural posture with reasonable manipulative effort. Repeated or sustained actions should be avoided.

7. Principle seven requires Size and Space for Approach and Use: Systems should be positioned so that they can be reached and used by all users, regardless of height, posture, or mobility. Important elements should be visible to both seated and standing users. All physical components must be within reach of a seated or standing user.

These seven principles are a good starting point for considering universal design. Of course, it doesn't apply equally to all situations. For example, principles 6 and 7 are important for information booth design but less important for word processing software design. However, they provide a useful checklist of considerations for designers and guidelines on how to achieve each principle.

Usability Heuristics:

1. System State Visibility: 

• This principle states that the user needs to know what is going on in the system. We must provide feedback on his/her behavior within a reasonable amount of time. This feedback is usually associated with action points, such as color changes, loaders, time-remaining graphics, etc. can be provided. 
• Example: Posting a tweet on Twitter makes a hissing sound. Google Drive shows the status of document uploads

2. Matching the system with the real world: 

• Is there anything in the application that users do not understand? It is also very important that your application speaks the language of your target user base. 
• Example: Neil Patel can say "login" on the landing page. Instead, he boldly decided to say, "Yes, I'd like Neil to teach me how to grow my business!" Set context and speak everyday language

3. User control and freedom: 

• Users often perform actions incorrectly. A marked "emergency exit" is needed to get out of unwanted behavior without going through a lengthy process. This principle dictates giving users the freedom to navigate and perform actions, and the freedom to undo accidental actions. 
• Example: Gmail flashes a message with undo the action if you accidentally deleted an email.

4. Consistency and Standards

• Users never have to wonder if different words, situations, or actions mean the same thing. Follow platform and industry practices
• Consistency is important because the submit button is a page that appears on every page throughout the site. If you display the data in a specific tabular format on the page, it should look the same. The following data is displayed in tabular form. If the header is displayed a certain way on the public page, it should be the same when logged in.
• Example: Submit button in the image is consistent for label size and style.

5. Error prevention

• Good error reporting is important, but the best design is one that is carefully designed to prevent problems from occurring in the first place. Eliminate error-prone situations or look for them and provide the user with a confirmation option before taking action.
• How many times have you reminded Outlook that your Gmail doesn't have an attachment, even though it says something is attached? Outlook intuitively scans your email looking for such keywords., to prevent mistakes by warning the user before sending.
• Example: Google search try to correct spelling while searching anything on search engine

6. Recognize instead of memorize

• Display elements, actions, and options to minimize user memory pressure. The user does not have to remember information from one part of the interface to another. Information required to use the theme (such as field labels and menu items) should be visible or easily accessible as needed.
• It is always better to suggest a set of options to the user than to force them to remember and type everything. The goal is to minimize user memory usage.
• Example: Quora suggests possible questions based on what you are trying to search

7. Flexibility and Efficiency of Use

• The shortcuts are designed for both novice and experienced users, as they can speed up operations for experienced users. Allows users to customize common actions.
• The interface should be flexible and convertible between novice and advanced users. This option is typically used when installing new software that prompts the user to proceed with a typical or custom installation. Advanced users can choose a custom installation and turn off unnecessary services.
• Example: The control Panel has options for User Accounts and Extended User Accounts. 

8. Aesthetic and minimalist design

• Interfaces should not contain information that is irrelevant or rarely needed. Each additional information item in the interface conflicts with related information items and reduces their relative visibility.
• The interface should be stripped of unnecessary elements and content that do not support the goals and objectives of the site. Considering this aspect, priorities become important. As a designer or developer, all the information displayed on the page is relevant. The product manager should ask the end-her user in such cases. Is all the information presented in the user interface necessary and useful?
• Example: Apple provides only basic information about features hidden under "Details". Look at the same product on a retail site to understand the importance of an orderly experience.

9. Help users identify, diagnose, and fix errors

• Error messages should be in plain language (no error codes), accurately describe the problem, and constructively suggest solutions.
• The error is unintentional in the user journey. You should check to see if these errors are explained in user-friendly language. You should ensure that exception handling occurs throughout your application to display relevant messages to the user.
• Example: In many cases, when you enter a fictitious username and password when logging in, you receive the error message "The username or password is incorrect." Here we do not tell the user if the username is invalid or the password is wrong.

10. Help and Documentation

• It is best if the system doesn’t need any additional explanation. However, you may need to provide documentation to help your users understand how to perform a task.
• If the user reaches this step, there is a problem with the interface. A great user interface allows users to navigate features without documentation or training. However, if there are users that you do not recognize, you should provide appropriate help with your product.
• Example: Go Daddy's Help page. While there is a search field, there are main categories and FAQs on the same page

 Future of Design Principles and Usability Heuristics

As technology continues to evolve, the role of design principles and usability heuristics will become increasingly important in shaping the user experience. With the rise of artificial intelligence and voice-activated devices, the focus will shift from visual design to voice design and how users interact with technology through voice. This will require designers to re-evaluate the current design principles and usability heuristics and adapt them to accommodate this new form of interaction.
Additionally, as user expectations and behaviors change, designers will need to be flexible and responsive to these shifts, updating their design principles and usability heuristics to align with the latest trends and technologies. For example, with the increasing popularity of wearable technology, designers will need to consider the unique challenges and limitations of these devices when creating their design principles and evaluating their designs using usability heuristics.