Accessibility and Usability are two concepts that seem to be closely related. But, too many people seem to have a distorted perception of them.
During last five years, those two words have come to the day-to-day work of almost every web developer, however, many professionals diving into this world are not aware of the importance of a good balance between both concepts.
First of all, what are those two words meanings?
is the ability of your web project to communicate its whole information to any user in the world no matter (a) his disability or impairment, (b) which device he's using or (c) which software is involved in the process.
is the easiness of use of your project. The simplicity of design, the tools developed to help your users to reach the full potential of your project and the clear order of information are all parts of your project's usability measure.
Reading both definitions one can think there's no conflict between the concepts of Usability and Accessibility, however, usually there's a risk of lowering one when you increase the other, and this could be difficult to perceive when you are developing your project.
For example, you might think a popup calendar tool is wonderful on your forms to avoid users sending wrong date formats or ranges, and you'll be right. But, you need to keep in mind that if you don't allow your users to also introduce dates through an input field, some of your users would not be able to introduce dates if they access your project from a device which is not compatible with the technology in which your calendar is programmed, or if they have an active popup blocker. And, if you only offer an input field to introduce dates, you could find that some users have difficulties filling them. For Example, maybe they are from a foreign country where date formats are different from yours, or maybe they have time perception difficulties if you don't offer them a choice of valid options.
Although Usability should be always on the mind of an interface designer, Accessibility shouldn't be discounted. I've often found people arguing that Accessibility is not a main target of their development because their business model is not focused toward certain users.
For example, a client that wanted to develop a DVD store said that their website didn't need to be optimized for text browsers, as blind people don't watch DVDs. We had to explain him that blind people still have brothers, cousins, parents, sons, etc. who can watch DVDs and have birthdays, promotions, and presents on Christmas from their blind relatives. Limiting your online store to certain clients in order to save on the development can drive you to lose a lot of profit in the long term. The fact that your product or your site is not aimed at a specific client type does not mean that those people cannot be your client. Maybe it could sound a bit odd from a marketing point of view, but consumers on internet expect accessibility no matter what product you are selling.
How can we reach that objective?
Well, sadly there's no simple answer for that question. There is not a golden rule to follow that will be valid for any case you'll find when developing your sites. However, there is something that you can always do that will ease your work in this matter: Use standards
The W3C is wearing a huge labour on standardize how web evolves and how it's perceived by users. And it's of great importance that we, developers, stick to their dogma at our best. Almost every today browser development is fulfilling W3C standards to a crescent degree, and those not doing so are condemned to disappear (remember when IE had +80% of browser market?).
So, if you stick to W3C (World Wide Web Consortium) standards you are fixing almost any compatibility problem you'll face in the long term. And you'll find that new standard technologies give better responses to eternal development questions; so stop using frames and start reading on HTML5 documentation.
Also, regarding pure Accessibility difficulties, the W3C has also created WAI (the Web Accessibility Initiative http://www.w3.org/WAI/
) several years ago. In this initiative you can find many resources that can help you make your sites more accessible to any user.
It's difficult to reach a correct balance between ease of use and universal access to the content. In the current context, each project must be evaluated separately, but the slowing increase in standards adoption will drive us in the long term to an internet where accessibility and usability will not be obstacles for web development anymore.