this sorta thing is pretty religious, so i'm just going to note the following points: 1. i've known traditional print designers that have jumped headfirst into

this sorta thing is pretty religious, so i'm just going to note the following points: 1. i've known traditional print designers that have jumped headfirst into html/css/js/etc and many of them have left behind artifacts that still live on the web: blogs they've themed, mini web apps, random code snippets, their own web portfolios, etc. investigate these and see if they mesh with what's on their portfolio or what they claim about themselves. 2. formally trained designers have had lots of experience with critique (and, by proxy, one hopes, critical thinking). Lots of crit is bs, but i tend to favor designers who are thoughtful and can back up their work critically or be honest about their motives. 3. you can assign "design tasks" if you want, but you need to be clear about what you're measuring and how your questions elicits that. If you're having trouble picking a design task, try a classic system design task (let's design usb from scratch...) and then see what that measures and if you can find some analog in your own problem domain. 4. the process is not foolproof and you will likely turn away very qualified people regardless of your metrics. 5. be clear about what you're looking for: do you want somebody that makes stuff look totally sweet, or somebody that solves problems well, or a person that codes monday, designs tuesday, and then specs out a new feature on wednesday... be realistic about your expectations. 6. people interpret the term 'designer' in a bunch of ways. lots of people take this to mean: "i can think about user flow, use visio to make wireframes, etc" and others take this to mean "how can this look awesome." others take this to mean "i thought through where a menu tree went in an enterprise java application" and others take this to mean "i make graphics design, do you need a logo?" and some others are like the wolf from pulp fiction, they just fix underspecified problems and are good brainstormers. none of these are better than others, they all are useful for different reasons and end-results. but what i'm saying is "you want a designer? why?" be honest about what specifically motivates your desire to hire a full time designer. this will make any interview you run easier to evaluate as a success or failure.