Interface design is an inexact science but it is a lot about science, about focus and about paying attention to the right things at the right times with regard to your user. The focal point of that activity is this user story. Well written user-stories, collaborative user-stories that you're developing with your team and creating a shared understanding, that really is the focal point. I thought we talk a little bit about design and the misperceptions about it and also how it relates the practice of design to what we're about to do. Things that I hear a lot about, what is good design from teams that I think are not very well-founded are that, it's like art and it's about flashiness and are a lot of colors or animation or demos, that isn't necessarily good design and it's almost more like art. Art is something that has its own intrinsic value like literature. So whatever the artist is doing, they're trying to express themselves. Design, we've job to do. We have some measurable goal that we're designing for. That's really a definition of design is to have some intent towards some goal, and so the other thing that design is also known about is this weird set of things about doing exactly what the user tells you to do and that thing user-centric, it isn't? Always having the answer, the Steve Jobs myth that he always knew what to do good designer, just goes in there and knows what's do. Those are also wrong. So let's talk about what is right and how we consistently achieve good design. We do it by getting the right focus, being consistent and constantly experimenting to see what's working for us. How do you get to that place? Well, you'll hear a lot, good design is simple just keep it simple, and that's not wrong I mean, good design is something you will experience as being relatively simple, what that really means is that it's focused on what you needed at that particular time and how do you get there, well, I would say that you need to have validated learning about who your user is, what they're trying to do, and why your proposition is better enough than their current alternatives to be actionable and investable, and so this foundation in the other areas that we've covered is super duper important to achieving that simplicity having the understanding, the confidence to get to this focus which is what in turn gets us to good simple designs. Let me give you a really specific example. A bad enterprise software will often have 20 fields when they really only use five, and when you ask the users why they don't like it, they'll tell you well there's so many fields and I don't know what to do with them and everybody uses them differently. So that's a good example very practical example of how this might work in actual practice and alternatively, how you would get to five fields. You can't just arbitrarily pick five fields that you think are the right ones, you have to know what jobs these users are trying to do, you have to test for that, you have to know what you're going to deliver to them that's better than the alternatives and that's what will give you the confidence and the testability to go forward and figure out, do you need two fields, five-fields, six fields and so forth. Consistency is really important and one of the easiest ways to get design wins and so for example, you should always use the same colors in the same typefaces for the same jobs and have a style guide. We'll talk a little bit about that. Also, if for example, you're using a signifier like a magnifying glass to mean zoom, you shouldn't also use it to mean search because that's confusing to the user. But more importantly, what we're going to look at is how we examined patterns and think about, what might the user be expecting to see here. So if we have a user who sees a magnifying glass and first thinks zoom, then that's a hint about where we should apply that magnifying glass signifier. Let's talk about consistency. I hate golf frankly, but sometimes I'm obliged to go and do it. One of the first things I learned is that, my goal when I go play golf is just to participate but not annoy my golfers who are usually more skilled than me. One of the things I learned is as long as I hit don't hit the ball too hard, it's not going to go too far afield, and so just by creating a style guide, and there's a reference here of where you can find this and it's in the course resources. Just by creating style guide and being explicit about how you're going to approach a given thing with typography, colors, and things like that, that'll give you better design, and also we want to make sure that we're constantly testing things. I'll give you a quick example of that. I worked on this project brand lattice with some collaborators, one of the things we were really unsure about was whether the user would, at this time when we were building it, understand that there was a drag and drop facility on the web. This is something that at the time and still to a degree, is relatively very common. So the idea was the user would grab these pictures and put them in these spots, and when we first tested it with this signifier here about what they were doing in this step, it was really bad. Very few people understood that's what they could do, but instead of really hammering this or completely changing it or throwing up our hands, we were testing and iterating really quickly and so for example, we just change the annotation slightly and we added this little arrow that you see, and it turned out that was enough. Now, I'm not trying to say that you automatically know exactly how your interface should look by doing all these things, but what you will get by approaching things this way is consistent usability and a nice testable view of what's working and what's not working and being able to declare hypotheses about how you should debug the usability problems that you're having so that you don't on the one hand ignore them or on the other hand overreact to them and make radical changes that really aren't necessary. So let's get into the details of how you achieve that.