Ben Shneiderman eight golden rules of interface design (Human Computer Interaction)

Eight Golden Rules Of Interface Design: This section covers eight golden rules that are applicable in most interactive systems. These principles are derived from experience and refined over two decades. These rules are well-received as a useful guide to students and designers.

1. Strive For Consistency: 

• Consistency can be achieved through elements such as fonts, color, shape, and position being consistently the same in all menus & screens, across, categories for a particular software.
• The sequence of actions that we perform must be in a similar situation.
• Usage of Identical terminology in prompts, menus, screens, capitalization, fonts, and layouts must be consistent throughout.
• Users should be able to do the same thing in the same way that they have been doing every time.
• consistency such as similar sequences of actions in similar situations makes it easy to learn.
• There should be a limited number of exceptions regarding the echoing of passwords and commands.
• Example: If the login button in screen 1 is placed at the left bottom of the screen and in screen 2 it is placed at the center of the bottom. This leads to positional inconsistency which is not a good practice.

2. Seek Universal Usability:

• The needs of diverse users must be recognized for facilitating the transformation of content.
• While designing make sure you keep in mind various audiences ranging from different expertise, ages, disabilities, and international variations.
• Users are classified as NOVICE, INTERMEDIATE, and EXPERTS. Experts tend to use lesser actions at a faster pace.
• Introduction of shortcuts for faster pacing and user interactions.
• Interfaces need to cater to all levels of users.

3. Offer Informative Feedback:

• Proper feedback should be provided for every user action. For frequent actions, the response can be modest whereas for infrequent actions the response can be substantial.
• Interfaces not just being communicative but also need to help users in terms of learning and feedback which tells them that they are moving in the right direction.
• For every action of the user, there should be feedback. such that there exists good interaction.
• Unless a user gets feedback. The user is unsure of the correctness of the action.

4. Design Dialogs To Yield Closure:

• The sequence of actions must be organized clearly into beginning, middle, and end phases.
• Providing feedback to the user after the completion of a group of actions gives the user satisfaction of accomplishment, and a sense of relief, and prepare for the next group of actions.
• Interaction dialogue needs to have a closure that is recognized by the user as the end of an action.
• The sequence of actions needs to proceed in a dialogue by engaging the user in a step-by-step manner.
• Similar to a mathematical expression where every enclosing bracket needs a corresponding closing bracket. Even the subsequence of actions needs to have a closing action.
• If we consider an example of an e-commerce website that provides users with clear information from selecting a product to the checkout ending with clear information.

5. Prevent Errors:

• Make sure the user interface is as user-friendly as possible. such that user doesn’t make any serious errors.
• Users can commit errors while interacting with the computers as well as while inputting or interpreting information.
• If the user commits an error the interface should offer simple, constructive, and specific instructions for recovery.
• For example, if a user is filing a form and if he types an invalid captcha or pin code then he should be redirected to update only the specific mistake and all other details must be saved and need not be entered again.

6. Permit Easy Reversal Of Actons:

• The interactions must be built such that retracing backward or reverse of actions can be performed which gives flexibility to users to explore new options.
• Make sure the actions are as much as reversible. such that user doesn’t feel anxiety, as the user knows that errors can be undone, and helps the user to explore unfamiliar options.
• The system should encourage exploration without incurring any kind of anxiety for users.
• one way to do this is to provide a traceable path backward of all actons.
• Reversibility may be single action such as a data entry task or a group of actions such as the entry of name and address.

7. Keep Users In Control:

• Allow users to always feel ‘in control’ of the system and of the situation. Make the user aware that he/she is in control.
• Users should believe that they are controlling the system and not the way around.
• Users should never feel lost.
• Experienced users don’t like it If any new features are added to the interface as it makes them feel new and uncomfortable.
• Changes in familiar behavior make users annoyed and make them unable to produce a desirable result.

8. Reduce Short-Term Memory Load:

• As Humans have a limited capacity for Information processing in short-term memory. 
• The interface design must be in such a way that it should not force users to remember huge amounts of information which make them overwhelmed like remembering information from one display and then using it on another display.