What are design docs?
I've talked to several people lately about potentially helping projects they are working on with the design. As a designer coming into a project, it's helpful for me if I can see the design work you've done already so I don't duplicate work, step on toes, or go in a different direction than has already been decided on. A lot of people have no idea what sort of thing I'm looking for though, so here are some things I find helpful (though by no means an exhaustive list!), and several of them can be useful to non-designers, too!
Note that it's absolutely ok if your project doesn't have these. They're good to have, but if you don't, that's good to know, too, and a designer can help you create them!
Project Goals
Basically, what problem are you trying to solve? What are your overall goals, how do you plan to achieve them, how will you know if you're successful in achieving them?
Ideally, a design starts with some problem you're trying to solve, then do research to verify and clarify the problem, come up with a number of possible solutions, and then validate which one will solve the problem best. But to be perfectly honest, the only projects I've worked on like that were in design school. Most projects seem to start with a pretty hazy idea of the project goals, if that, then jump straight to how to implement the solution. That's ok, but you do need to figure out what problem you're solving before you know if your solution is solving it well or not.
I've found these things to be helpful not only to me in designing and validating designs, but also for keeping conversations and features focused. Goals help you decide what work is important, what isn't, and what features outright detract from your purpose.
Research
Any research involved in creating the goals and plans above, or research suggesting changes in your audience over time and how people are actually using your product. This can include contextual research, interviews, usability studies, market research, surveys, statistics and analytics, or really, any other work you've done talking to people about the problems you're solving and how they use your product—it doesn't have to be formal, anything you have is useful.
If you don't have the up front research about your goals—or even if you have, since things can change over time—it might be a good idea to have your new designer do that now with the people who are currently using your project. You may find out that it does poorly on the things you thought you were doing, which can sting if you're really attached to the idea, but that people are using it to solve an entirely different problem, which can be really enlightening. These are good things to know, and you can take them back and revisit your goals and solutions.
Style Guides
These can be visual and granular like what colors to use and how to style buttons, more structural, like what context calls for what sorts of widgets, or verbal, like what tone of voice to use in different parts of the interface. They can also include design assets like logos, photoshop templates, color palettes, etc. Here are some examples of nice ones:
Style guides are useful to maintain consistency across the whole system and help developers put new pages together faster using existing patterns, but to remain useful they have to be kept up to date with new design patterns as they are added.
Other Design Artifacts
- information architecture (think sitemap, or more generally, what things should be grouped together?)
- interaction descriptions or diagrams (when this page is displayed, if user clicks this do this...)
- sketches, wireframes, mockups, and prototypes
- discussion surrounding all of the above
If you haven't had a designer before, you may not have anything formal, but even just sketches, annotated screenshots, and white board diagrams can be helpful. And in particular, if there's an online record of the discussion on new features, for instance why something was done one way and not another, that can be particularly useful in absence of more formally documented style guides and research.