Recently we were asked what we thought the most widespread web usability issues were. We have evaluated over 140 websites in the last 18 months, and repeatedly see the same website design mistakes, most of which are easily corrected. The Top Ten mistakes are:

1. Poor categorisation and labelling of information.
Problems with site structure and the names of the main categories are among the most damaging problems for a website. For example, the <a href=”http://www.pumpkinpatch.co.nz”>Pumpkin Patch website</a> has ‘Shopping’ and ‘Product Guide’ categories – neither of which actually show the range of kids clothing that they have for sale. Too often websites reflect the internal structure and labels used by the organisation, rather than those of their customers.

2. Poor navigation design.
Even if a site is well organised and information is in clearly labelled categories, the design of the navigation elements can undo all the good work.

3. Cluttered page layout.
Many pages are difficult for users to scan because the design is cluttered. Information isn’t aligned and there is too much unused space. The most important information on a page isn’t clear at a glance. Few pages make effective use of section headings and sub headings so that it is obvious how the information on a page is structured.

4. Inconsistencies with web design conventions.
People spend most of their time at other sites. That’s why it’s crucial that your site follows standard design conventions and behaves as visitors would expect. Inconsistencies will make your site harder to use and less intuitive.

5. Too little content.
It is amazing how little thought goes into understanding who website users are and why they are using a site. A luxury lodge website we worked on earlier this year, for example, did not tell visitors how many people could stay at the lodge at one time, or whether they could bring their own food.

6. Too much content.
While too little content can be a problem, we more often hear complaints about too much content. Users balk at the idea of reading long pages of text online. Overseas research has shown that people read up to 25% slower from a computer screen as opposed to paper. Our own experience supports this – at ACC, for example, people preferred pictures and diagrams over words to illustrate injury prevention principles.

7. Poor use of links.
People move around on the web by clicking on things. That’s why it’s got to be obvious what a user can and can’t click. Sites should link useful pieces of information together. For example many university sites don’t link their subjects pages to useful pieces of information such as timetable details, or pre-requisite papers.

8. Poorly implemented forms.
Despite their popularity, most online forms still make basic mistakes. Compulsory fields aren’t highlighted and users aren’t given instructions on how to enter dates and phone numbers in the correct format. My personal favourite – entered information is not saved until the form is complete – forcing users to re-enter all information if they make a mistake.

9. Poorly written error messages.
An ideal website prevents people from making mistakes in the first place. At the very least a website should help users to diagnose and recover from errors. Instead most error messages are terse and impolite and use obscure jargon and vague phrases.

10. Poorly implemented search.
Many people browse for information on a website and use search engines only as a last resort. Your search engine needs to be bullet proof, or you risk irritating already exasperated users.

Note: Jakob Nielsen has also recently released his Top Ten Web Design Mistakes of 2005