A summary about usability
Usability has much to say, but I will split in several posts, starting with this, introducing the subject, telling a small history of usability, their creators and objectives.
To Hix and Hartson (apud Heemamm, 1997), usability is the combination of easy learning, high speed execution of tasks, low rate of errors, subjective satisfaction and retention of knowledge of the interface, ie the user even after a long time without interacting with the interface, still remembering how to use. For Bevan (apud Days, 2003) suggests "usability" as a technical term to refer a use of an interface. According to ISO 9241, "usability" is defined as efficiency and satisfaction with which users achieve their objects in a system.
When we talk about usability, we are referring to how well users can use the resources of a website or software. "User Friend" is a world known term to determine if an interface helps the user, even if this is a website, software or game. However, "user friend" is different from usability, it's not a definition based on scientific fundaments, if you say that an user interface is "user friend", it gives no substrate and metrics, it is a vague term, and generic. It's better to say that an user friend interface it's an adjetive.
Nielsen joined the term "usability" into five attributes capable of measurement on an interface, which follow:
- Ease to learn;
- Efficiency of use;
- Ease to memorize;
- Low rate of errors and
- Subjective satisfaction
With these attributes, it is possible to measure the degree of usability of an interface, and become a more specific term. Tell if an interface has a high or low usability now it is possible.
Note that the usability is one of the most important factors when we are talking about a software, website or game. Because the user must first understand the navigation of the interface, before finally reaching the contents, in this case is what we is wanting to sell. Winckler & Pimenta (2002) listed some classics troubles you can have on an interface, which are:
Navigation: When the users has troubles to finding the desired information or functionality. They don't know to return to a previous page (in case of a website) or find a feature of the software. The figure below illustrates a software with this problem:
This is a video convertion tool, this software contains problems of navigation. Note these buttons, options and fields to fill, it's a mass! You hardly remember the control positions and you'll need to read all the interface again every time you use. And if you're using for the first time, you'll need time to adapt.
Multimedia Resources: Excessive use of videos, pictures and colors in the composition of a website. The figure below shows a website with this problem, although not so serious. Among the problems of multimedia resources, we can mention the abuse of colors, images, text highlights, font sizes, etc.).
Technology: Browser incompatibility, operating systems and hardware (connection speed). Very common among software and games, however, there are some websites that are very limited between browsers as Microsoft Internet Explorer versus Mozilla FireFox. The figure below shows a website accessed via FireFox, requires Microsoft Internet Explorer. Certainly the website will have a loss of visits and potential consumers. Looking all the functionalities, there is nothing special to run only on IE.
In our next post we will begin to explore more about Usability and talk about the Usability Engineering. This was more an introduce the subject to heat our engines!