I spent the past two days running usability tests on websites that sell financial products like life cover, funeral policies, and annuities. The target market is lower-income users who access the Internet at least once a day on a desktop at home or work, or on their phones. They are, for the most part, tech literate, and very used to finding their way around the Internet. I wanted to document some of the more general findings while we’re knee-deep in analysis and everything is still fresh.

What follows is a list of interaction design elements that I believe should never, ever be used on a website. They might seem like small issues, but I’ve seen time and again how small things add up, and eventually end with frustrated users who abandon a site altogether. Also, if you’re tempted to think that your users are different and somehow more sophisticated than the ones we tested, please consider the growing digital usability divide.

So, here it is — an incomplete, top-of-mind list of usability sins your website should never commit, based on data gathered through in-person usability testing:

• Don’t use an asterisk (*) to mark required form fields — especially if there is no explanation of what the asterisk means. Most users do not understand this at all. Instead, state that all fields are required unless indicated otherwise, and then mark optional fields with the word (optional). By the way, Luke agrees with me on this one.
• Don’t open links in new browser tabs. Tabbed browsing is for advanced users. If you open a page in a new tab, most users will get lost, start clicking the back button, and then not understand why they can’t get back to where they started. Remember that they’re not focused on the chrome when they click a link, they’re focused on where they’re clicking. So it’s very easy to miss the fact that a new tab has opened.
• Don’t have an FAQ page. Most users don’t know what FAQ stands for, and besides, it’s bad practice to answer questions outside the context people want to ask them in. Figure out where in the process each question in your FAQ might come up, and provide the answer right there within the flow. Don’t expect people to click to a different page to find the information they need.
• Don’t use PDFs at all (unless you’re explicitly stating that it’s a downloadable research paper or something). Many users have no idea what a PDF is, and can’t even tell when they’ve clicked on one. There’s no reason to have your rates/menus/timetables as a PDF as opposed to standard text. This was a recurring theme, but one user in particular clicked on a PDF, didn’t realize it, and continued interacting with it as if they were still on the website.
• Don’t give table rows highlighting mouse-overs if the rows aren’t clickable. This confuses users. Any mouse-over movement gives users a trigger that they can click on the thing. Don’t think they’ll look at the cursor and distinguish between an arrow and a hand — most don’t look past the hover effect.

This is obviously a fairly random list of UI transgressions, but I feel like we talk about the big issues so often that we tend to skim over the smaller ones that can really add up. If you were observing the usability tests we ran this week, you would have felt the same way I did when you saw person after person struggling with the most standard of UI conventions. Let’s just not do these things, for the love of the web and everyone who uses it.