So now we're going to dig into usability heuristics and some associated principles and laws. Heuristic evaluation is one of those methodologies that I always wished I had known about earlier in my career. I had done a lot of interface design work, and really having these usability heuristics available to apply to assess a design is one of the most valuable approaches that I think I can share with you. I wish I had learned about it sooner. We'll talk about how they work, how you can use them in various phases of your UX work. We'll also talk a little bit about some design principles and some laws of UX. Before we do that, I think it's important that we agree that even though we're breaking these things down into heuristics, principles, and laws, really all of them are essentially guidelines to effective design that other people have run into. Heuristics are usually defined as more of a rule of thumb or a practical method. A principle has a little bit more concrete to it, maybe something that's a applied theorem for a given field. And of course a law is even more solid than that. But in this case, almost all these things that we're talking about are really intended to be guidelines for your designs. So the method of heuristic evaluation is fairly straightforward. Generally it's suggested that it's done by an expert. But I have found that most people that know a little bit about interface design, once they're exposed to the heuristics, it's fairly easy for them to apply those heuristicsto a design. And what you're doing is you're letting a reviewer consider a given heuristic and then look at a design to see if it meets the guideline. It's fairly straightforward, and what you'll end up with is a list of issues where the design doesn't meet those heuristic guidelines. Then you can decide what you need to do about it, if anything. What's important here is that, both in my experience and the literature, a heuristic evaluation finds a different set of issues with an interface than you'll find by testing with actual users and having them try to do tasks. So don't do one or the other, try to do both. Because both of them are valuable and both will find issues that you'll need to know about. Usability heuristics of the initial set was developed by Jacob Nielsen, he's fairly famous for them. There are ten heuristics that he put together around 1990. There are a lot of people that have put together other heuristics sets since then, and we'll talk about some of that, but let's take a quick walk through Nielsen's heuristics. The first one is visibility of system status. If you remember, talking about Norman's design goals, people should be able to look at a system and know what state it's in. I think that's reasonable, sometimes it's hard to do. Match between the system and the real world really talks about mapping how a user thinks about using a device to some mental model that they have of maybe some similar process or similar device. User control and freedom, a user should always be able to back out of some issue that they've gotten into by mistake. Whether that's an emergency exit or an undo, redo sort of functionality, it's good to think about how people can have the freedom to get out of something they've gotten into. Consistency and standards, if you're developing an interface, every time you interact with that interface, even if it moves to a different screen or to a different set of controls, there should be conventions that are followed that keep things working the same way. That don't take the user out of the paradigm that they understand to work with that device. Error prevention is important. If it all possible, you should avoid putting the user into situations where they can create an error. Recognition rather than recall, this even came up during our discussion of cognitive psychology. People much, much better function when they just have to recognize something rather than remember it. So whatever you do, try and make actions and options as visible as possible. Then flexibility and efficiency of use, this actually talks to the fact that systems are often used by novices, average users, and expert users. A novice user might do better if they have some kind of a tool that helps them through a task. Where an experienced user might want some sort of accelerators to do the things that they already know how to do. So you have to think about how you tailor frequent actions for those different sets of users. Aesthetic and minimalist design, people respond better to a device that has nice aesthetics, that's just the way it is. It's important that you don't clutter an interface with anything that's irrelevant or may not be needed. If errors are going to occur, it's important to help users recognize, diagnose, and recover from those errors. We don't want to give them error messages that they can't use to help them figure out what's going on. Then finally, help and documentation. If it's possible for the system be used without documentation, that's great, but if not then that text or that prompt should be nearby and clear, so that we can help the user get through what they need to do. Here's a set of other usability heuristics. Tog actually works with the same firm as Nielsen does, and Norman for that matter. And he's developed a very, very long list of interaction principles. Great to take a look at, but a little too long to use as a heuristic evaluation, but it might be good as a design guide. There's other ones here for mobile interfaces, medical devices, children's devices. Lots of people spend a lot of time looking at heuristics for specific classes of devices. Should there be a set of heuristics for embedded and connected devices? Maybe so, maybe that'll be a research topic for one of you. Now we're going to talk about design principles a bit. And this is really, again, a set of guidelines or rules that people have come up with based on their understanding of a certain user population or of people in general. The three that were going to take a look at here are Edward Tufte, the Royal National Institute for the Blind, and the NCSU principles of universal design. These are some great examples of principles. Tufte, if you don't know him, has written a number of books that are really in and of themselves works of art and deserving of your attention. But they talk specifically about information and getting it across to people either through interfaces or through documentation or through presentations. He's fairly famous for the ideas of the small multiple and Sparklines. Sparklines are shown here, and it's really just a small graph that sits next to a number to give it some context. You can see these now in Excel and in other tools. I had the opportunity to sit in a lecture that Tufte gave, and I took 15 pages of notes in a few hours, it was really engaging. These are his grand principles, and they really talk to what you should be striving for when you're trying to get information across. You want to be able to show comparisons, like in this picture of small multiples. Show causality, if it's there. Integrate multivariate elements, if something is based on multiple inputs. Integrate words, and numbers, and images, etc. So you can take a look at this list, I really have found his principles and his books to be extremely engaging. I highly recommend you take a look at them, if you can. Again, the Royal National Institute of Blind People put together a checklist related to issues that older or disabled adults have. This is another excellent resource. I was involved in the design of some devices for an aging population, an this list was invaluable. There's also a book by Fisk and his cowriters called Designing for Older Adults. If you ever do get into the business of designing for an older population, do take a look at both of these resources. The Seven Principles of Universal Design is actually a poster from North Carolina State, and it's readily available. It talks again at a very high level. About the principles that you should use when you're designing devices. Things like tolerance for errors, simple, intuitive use. You'll see echoes of the usability heuristics in this list. Then if you're in the user experience community, you'll start to see some laws that people mention. The most famous one probably is Miller's Law, that says people can keep in short term memories 7 plus or minus 2 items. Often this is used as a way to measure how many items should be in a menu for people to choose from. That's not really the intent of this. It really talks more about what people can keep in mind, not what they're recognizing in making decisions about. That really is more around Hick-Hyman Law, where you're talking about the time it takes to make a decision, based on the number of choices you're presented. Fitt's law is also fairly famous, in that he developed an equation that helps you figure out how long it takes to target a specific part of an interface, when those things are away from a home position. The Doherty Threshold really talks about how much more productive you can be when there's not a delay for the computer responding to your input. The Power Law of Practice, the first 50% of things you learn goes quickly. The other 50% takes more time. The Pareto Rule, you've probably heard of, 80% of the work is around 20% of the functionality, or what have you. Zipf's Law is about word frequency, again, the aesthetic usability effect. If something is more aesthetic, people will find it more useful. And then Parkinson's Law really comes back to projects. Most tasks will inflate to use all the available time, another reason to keep a WBS of the schedule. So in summary, again, heuristic evaluation and usability heuristics, in combination with user-based testing, give you the most powerful way to find the design issues that you might have in what you're putting together. Don't avoid these things. Look into both approaches and apply them as much as you can in your designs. It really does have a significant impact. And you can look at using these methods where it's appropriate, in the analysis phase and also in the verify and validate phase. So take a look at these things, consider how they impact you. In the next step, we'll talk about sketching, thanks very much.