- The importance of interface usability is not exaggerated. Users don’t buy, register, or subscribe to the updates. What are the reasons for such behavior? The reason is that the website has unfriendly and hard to understand interface. Usability helps to meet the expectations of the web sources owners as well as users. Before World Usability day we decided to collect and recall the main Usability principles. They are all known, but sometimes these basics are forgotten. Supposing that some of them will help avoid mistakes and create great websites.
Here are the 5 Usability rules:
1. The rule of the 7 points
Human brain has limited abilities. Especially, it relates to memory and attention. A person can keep in short-term memory no more than 5-9 entities. Therefore, you shouldn’t place in the website navigation more than 7 points.
2. The rule of the 2 seconds
The less the user waits for the response of the program, site or application, the more likely it is that the necessary action will be done. It depends on the goal of the site or app. 2 seconds is the optimal time interval of the program response. Think twice before you put on the site a heavy flash intro or picture, because it could be the reason of the users’ refusal to check out your site.
3. The rule of 3 clicks
No one likes to surf the page, in search of the necessary information and functionality. The visitor should be able to get from the main page to any other page of the site, making no more than 3 clicks. In addition, it contributes to a more successful indexing site search engine.
4. Fitts Law
The model of human movements published by Paul Fitts in 1954, determines the time necessary to move quickly to the target zone as a function from the distance to the target and the size of the target.
In other words, the law can be explained as follows: it is easier to point at bigger button, than smaller. But it doesn’t mean that the biggest button is the most important. The Fitts Law allows to determine the size of the interface elements, their location and relative position on the screen in accordance with how simple (or, on the contrary, difficult) their use should be. For example, if an interface object, such as a link, is already large enough, it makes no sense to make it larger.
5. Inverted Pyramid
This principle is saying, that the article on the site should begin with a conclusion, followed by key points, and conclude with the least important information for readers. This is optimal for the web, where the user wants to get information as quickly as possible.
Nevertheless, any interface should be tested. Don’t forget about usability testing, because it is vital for usability interface. Testing should be on every part of usability design process.