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Today's article will focus on a specific Heuristic framework, the ''Connell Full Principles Set".

As a UX designer, it's common to utilize Jakob Nielsen's 10 Usability Heuristics for User Interface Design as the approach for heuristic evaluation. However, fitting all the usability issues discovered during an assessment into Nielsen's heuristic framework felt often limited and constrained that several UX professionals would come across user experience problems that were worth discussing but didn't fit into the predefined mold.

Choosing the right heuristic evaluation approach is critical to uncovering usability issues and improving the user experience. While Nielsen's heuristics are comprehensive and widely used, they may not always be the best fit for a particular project or situation.

This article will explore and provide you with one alternative heuristic approach that could help you choose the appropriate method.

We will discuss the following topics:

Who is Dr. Iain Connell?

Dr. Iain Connell is well-known for his contribution to the field of human-computer interaction (HCI literature).

After completing a DPhil in Psychology at York University, Dr. Connell joined the Interaction Design Centre (IDC) at Middlesex University. He worked alongside fellow researchers, Ann Blandford and Thomas Green on a research project called CASSM, which stands for Concept-based Analysis of Surface and Structural Misfits.

CASSM is an innovative research method for usability evaluation that utilizes entity analysis instead of detailed heuristics task analysis. Its focus is on identifying potential misalignments between the designer and user views of an interactive system by examining the entities and actions the user interface system displays.

Cornell's set of heuristics research in universal designs was established by a group of architects, product designers, engineers, and environmental design researchers at the Center for Universal Design at North Carolina State University. These heuristics aim to provide guidance in the design of environments, communications, and products.

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What is HCI and how does it work in user experience?

What is HCI and how does it work in user experience

HCI (Human-Computer Interaction) is a field that focuses on designing computer systems and other technological interactive system interfaces that are intuitive, efficient, and user-friendly. The goal of HCI is to ensure that assistive technology works for people, rather than the other way around.

To make HCI work for people, designers, and developers must consider a range of factors related to human behavior, cognition, and perception. They must take into account the needs and preferences of different user groups, as well as the cultural and social context in which technology is used.

Some of the key heuristics that can help make HCI work for people include:

User-Centered Interface Design

This approach involves involving users in the universal design process from the beginning so that the resulting technology meets their needs and preferences.


HCI must be designed to be easy to use and understand, even for people who are not technically proficient.


HCI must be accessible to all people, including those with disabilities or special needs.


HCI should be designed to have clear visual cues and intuitive interactions so that users can easily understand how to use it.


HCI should provide feedback to users about what is happening when they interact with it so that they can understand the consequences of their actions.

By focusing on these principles, designers, and developers can create technology that is not only effective and efficient but also user-friendly and enjoyable to use.

Let us now dive into Connell's heuristic evaluations framework:

The Full Principles Set by Dr. Iain Connell

Heuristics Requirements and Functionality

When designing a system, it's important to ensure that the system's intended functionality aligns with the requirements and expectations of its users. This is where the heuristics of Requirements and Functionality come into play.

Requirements and Functionality ensure that the system does what it is intended to do and that its intended users are well understood by the designers. These principles work hand-in-hand to guarantee that the system functions as expected and meets the needs of its users when a user makes an appropriate action.

1. Functional needs

The set of functions offered by the system should align with the needs and requirements of its intended users. This means that the system should be designed to perform the functions that are most relevant and important to the users.

2. Requirement needs

Accurate determination of the characteristics and functional requirements of the intended users is crucial to the success of the user interface system. This includes identifying the user's preferences, knowledge, and skills to ensure that the system is designed to cater to their specific needs.

3. Functional organization

The organization of the system's functions should match with the expectations and knowledge of the intended users. This means that the system should be organized in a way that is intuitive and easy for users to navigate.

4. Functional provision

The system's functions should provide the best means of performing the required operations. This includes ensuring that there is no redundancy or under-provision of functions, with only those functions that are required and no more. These principles are typically applied during the requirements analysis method to ensure that the system is designed to meet the needs of its intended users.

User: System Principles

These principles focus on the interaction between the user and the system, specifically the sequences of choices and actions made by the users in response to the system, as well as the types and nature of messages, displays, and other outputs presented by the user interface system.

The range of usability problems involved includes the locational and navigational information provided to the user, the feedback given in response to user commands, how errors are defined and handled by the system, the range of choices available to the user during the interaction, and the terminology and language used in the user interface system's text messages and displays.

5. Minimum Steps

Make it easy for users to move between system states and functional components with minimal usability steps. Avoid unnecessary repetition of step sequences and ensure there is a minimal number of steps between related usability components.

6. Minimum Retraction

Make it easy for users to move between system states and functional components without unnecessary retracing of steps already taken.

7. Memory Load

Avoid complex input formats whenever possible. If necessary, provide instructions on the required format and default values.

8. Error Management

How errors are defined and whether commonly used error classifications, such as Donald Norman or James Reason research, accurately capture the full spectrum of errors made, for example. Prevent erroneous user's actions before they occur rather than identifying them afterward. User actions with serious consequences should be completely prevented, or a warning given before the final initiation.

Provide necessary information on the consequences of the error and any alternative actions. User actions with less serious or trivial consequences should be retractable, including a general "undo" usability function.

Complex inputs should be retractable and modifiable before initiation. Use affirmative and positive tones in usability error messages and warnings.

9. Feedback

Ensure the status of the system is visible to users at all times. Provide immediate confirmation of user-initiated processes and indicate that all user interface system processes are continuing.

For processes longer than 10 seconds, indicate the elapsed duration or completion time. Provide confirmation for all user inputs and appropriate feedback for continuous user's input.

10. Locational Information

Ensure users know where they are in the user's interface system and what steps they can take. Label every system state (screen, window, dialogue box) and indicate its relationship to other states.

Provide a range of user options at each state, including a return to the previous state. Avoid states from which there is no exit. Clearly distinguish different functional modes.

11. Locational Modes

Clearly distinguish different functional modes where states represent them (e.g., windows, screens). Indicate the currently active state if different states can be opened concurrently. Allow users to determine which states are currently open and switch between them.

12. Choice Availability

At each system state, provide appropriate user options. Maintain a balance between the number of steps required for particular operations and the number of options available at each step. Avoid overwhelming or impossible-to-encompass options at any step. Ensure each option is functionally distinct from the others.

13. Terminology and Language Style

Match terminology and language style with the intended users' experience and background knowledge. Use a minimally sufficient size, format, and complexity for each piece of text to convey its meaning.

14. Visual Metaphor

Encourage users to create a coherent conceptual model of the system's functions and organizational structure using metaphors from their environment or task domain. Use usability visual and other representations of real-world objects and operations, particularly visual metaphors.

User Principles

These principles pertain to the system's responsiveness to user preferences and the necessity to tailor the system accordingly. They also impact the user interface system's ability to handle multiple types of user input. Additionally, these principles cover the content of the production method and the importance of highlighting certain aspects of it.

15. Functional Modification

Users should have the ability to customize or adapt certain aspects of the system's functionality and organization to meet their level of experience or preferences. This may also extend to other similar universal design applications or versions of previous systems.

16. Step Modification

The system must allow users to modify certain aspects of its workflow and structure to better suit their level of experience or interests. This includes the ability to assign shortcuts to frequently used functions or procedures, as well as the ability to edit default or assigned shortcuts.

17. Multiple Initiation

In a large system, it should be possible to initiate the same task from different starting points and in different orders. Therefore, the beginning of a project can start from different stages in various phases of the process.

18. Multiple Inputs

Systems with mixed inputs (e.g. allowing for both mouse and keyboard input) should provide users to utilize more than one input mode.

19. Accuracy of Content

All usability information conveyed by the system should be accurate, unambiguous, and clear.

20. Salience

Certain parts of the system may be especially important or unique compared to other user interface systems and may require special attention. These aspects should be given due consideration.

21. Consistency

The process required for performing tasks should remain consistent. Moving between resources should always function predictably, and the configuration of resources or states should not vary depending on the type of work being done. Therefore, the various options available from a state should not change, nor should the relationship between different elements and underlying components.

Vocabulary and language styles should be consistent in universal design across regions and states, just as the format of information content should remain consistent within a single genre. All information and details should follow a consistent form and format, and any important content should be presented in an orderly manner.

System Performance Principles

These standards relate to the degree to which the system prevents or restricts the user's ability to physically move parts of its components. In addition to responding to the input and processing of screen elements, it includes the ability to change between the active process and the elements in it, at any stop between entry and the start of the usability process.

22. Manipulability

Users should have ample flexibility to switch between usability components and configure the interface. In a multi-task or multi-state system, there should be a way to access hidden or private states and switch between active states. In the drawing process, objects should not be unnecessarily fixed to a window or prevented from interacting with other objects without justification.

23. Responsiveness

The system should respond promptly to user actions with minimal delay in system initialization (as opposed to processing time). Physical components moved by the user should not present any resistance to movement. Additionally, the system should provide feedback to the user to indicate that their actions have been registered and are being processed.

Perceptual and Motor Principles

These principles pertain to the sensory and motor demands placed on the user by the system, including the usability visual and auditory load presented to the user, the number of physical actions required by the user, and the clarity and contrast of the screen images, as well as their organization.

24. Visio-Perceptual Load

The system should not overwhelm the user with excessive visual or auditory load, including the complexity, design, color, and structure of each component in a multi-state system.

25. Audio-Perceptual Load

The auditory load presented by the system should not be excessive. The audio output should be used sparingly, such as to indicate salience, and volume levels should be adjustable.

26. Motor Load

The system should require minimal physical activity from the user. The number of usability steps in a sequence should be minimized, and the motor activity required to complete each sequence should also be reduced.

27. Perceptual Clarity

All graphic elements should be easily recognizable and distinguishable from one another. The descriptive text should be legible by adjusting the font size, style, and line spacing.

28. Perceptual Contrast

The contrast between visual elements and their background should be sufficient for clear distinction without being excessive. Positive polarity (dark and light) is preferred over negative polarity (light and dark), and color conflicts (such as red-green, blue-black, blue-red, or blue-yellow) should be avoided. Bright colors should be used sparingly unless they indicate a special status.

User Support Principles

These principles pertain to the availability and nature of online assistance that the user can access, including general help that can be searched for and context-sensitive help.

29. General help

Online help should be provided and must be accessible from any article or resource. It is possible to search for the object in different ways.

The number of items should not be limited; Little attention is paid to the steps necessary to complete the work. Examples and examples from the system should be used whenever possible. The way keys in the resource should match those used elsewhere.

30. Context-Sensitive Help

In addition to the online assistance, the material relating to the context of use must be available from each status or system component. This is especially important for error states, where the hardware should enhance, not degrade, the information already provided. Help that is sensitive in nature should not only replicate or allow retrieval of general help related to the task attempted.


Heuristic evaluations in UI design can lead to disastrous outcomes when overused. While they contain relevant wisdom for the user experience, it is important to not rely on the heuristic evaluation too heavily. Instead, let this article serve as a gentle heuristics education guide for you to know if Connell's user interface design principles could help you in coming up with an intuitive universal design method.

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Mary Ann Dalangin

About the author

A content marketing strategist and a UX writer with years of experience in the digital marketing industry.

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