What is Cognitive Walkthrough ?

Cognitive walkthrough is one of the usability inspection methods. Cognitive walkthrough involves one or a group of evaluators inspecting a user interface. In cognitive walkthrough, the evaluators go through a set of tasks and evaluate its understandability and ease of learning.

The user interface is often presented in the (a) form of a paper mock-up, (b) a working prototype, (c) a fully developed interface.

The input to the walkthrough also include the user profile, especially the users' knowledge of the task domain and of the interface, and the task cases.

The evaluators may include web designers, webmasters, human factors engineers, software developers, marketeer, etc.

Jakob Nielsen has written numerous articles on usability inspection, heuristic evaluation and cognitive walkthrough.

What is Heuristic Evaluation ?

Heuristic evaluation is a discount usability inspection method for website, portal, software, games, etc that helps to identify usability problems in the user interface (UI) design.

Heuristic evaluation specifically involves evaluators examining the interface and judging its compliance with recognized usability principles (the "heuristics").

Heuristic evaluation is the most popular type of usability inspection method. Heuristic evaluation is relatively cheap to implement.

In conducting heuristic evaluation, a set of heuristics is used to guide the evaluators in inspection the user interface. One popular set of heuristics is the Nielsen’s Ten Heuristic Principles.

What is Usability Inspection?

Usability inspection is a set of usability evaluation methods where a usability evaluator inspects a user interface.

Usability inspection is in contrast to usability testing where the usability of the interface is evaluated by testing it in usability lab on real users and/or mock users. Usability inspections can generally be used early in the development process by evaluating prototypes user interface; this cannot be done using usability testing.

Usability inspection methods are generally considered to be cheaper to implement than testing on users.

Web design and usability guidelines with Very High "relative importance"

Web design and usability guidelines had been researched according to rating of "relative importance."

Below is the list of web design and usability guidelines with "relative importance" rating of 5 (based on rating of 1 to 5).
Use an Iterative Design Approach
Provide Useful Content
Use Black Text on Plain, High-Contrast Backgrounds
Ensure Visual Consistency
Provide Consistent Clickability Cues
Use Clear Category Labels
Ensure Usable Search Results
Ensure the Homepage Looks like a Homepage
Do Not Use Color Alone to Convey Information
Eliminate Horizontal Scrolling
Allow Simple Searches
Create a Positive First Impression of Your Site
Organize Information Clearly
Display Information in a Directly Usable Format
Detect Errors Automatically
Put Critical Information Near the Top of the Website
Do Not Display Unsolicited Windows or Graphics
Label Data Entry Fields Clearly
Use Unique and Descriptive Headings
Distinguish Required and Optional Data Entry Fields
Evaluate Websites Before and After Making Changes
Minimize User Data Entry
Format Common Items Consistently
Provide Feedback on Users' Location
Set and State Goals
Show All Major Options on the Homepage
Provide a Search Option on Each Page
Design for Common Browsers
Put Labels Close to Data Entry Fields

The above web design and usability guidelines are useful for web designers and web master in the design and development of website/portal which is high in usability.

Top 4 Usability guidelines (HHS and GSA)

HHS and GSA had conducted a research to determine the important Web Design & Usability guidelines.

Top 4 usability guidelines based on "relative score" are as follows:
Use an Iterative Design Approach
Provide Useful Content
Use Black Text on Plain, High-Contrast Backgrounds
Ensure Visual Consistency

All the above 4 usability guidelines had the "relative score" of 25.

Next to these were the usability guidelines having "relative score" of 20.
Provide Consistent Clickability Cues
Use Clear Category Labels
Ensure Usable Search Results
Ensure the Homepage Looks like a Homepage
Do Not Use Color Alone to Convey Information
Eliminate Horizontal Scrolling
Allow Simple Searches
Create a Positive First Impression of Your Site
Organize Information Clearly
Standardize Task Sequences
Use at Least 12-Point Font
Use Video, Animation, and Audio Meaningfully
Order Elements to Maximize User Performance
Use Mixed Case with Prose
Facilitate Scanning
Group Related Elements