Nielsen's fourth heuristic is consistency and standards, and he says, "Users should not have to wonder whether different words, situations, or actions mean the same thing." Also, it's important to follow platform conventions. Why is this important? Well, again, this allows us to leverage users' schemas. So, allow them to take advantage of patterns of interaction, and patterns of information organization that they've learned from using one system or one part of a system and apply it to a new system or a new part of that system. Being consistent allows us to present a coherent conceptual model, which makes it easier for users to learn how to operate the system effectively. Consistency and standards show up in a number of different places in the design of systems. So, firstly, it shows up through the consistency of language, layout and behavior. When designing systems, we often have many choices about what to call system functionality. We might decide whether to call a particular function search or submit query, or save versus commit, or create versus new.... While it's important, as we learned in an earlier heuristic, to use terms that are familiar to a user, there might be many terms that would work in a particular situation. What's important here is that you use the same term in the same way throughout the system. So, the user doesn't have to wonder if save means the same thing as commit, or whether search means the same thing as submit query, and if they mean different things they should actually do different things so the user can learn what those different things are. Consistency applies beyond language, however, also to layout and behavior, and to look at a good example of how consistency can be applied let's look at amazon.com. So, if I look for different types of products on Amazon. So, let's say, in this window, I look for a coffee makers, and over here I look for running shoes. You'll see that there's some slight differences in the way that the search results are displayed, but they're by and large fairly similar, but if we look at the individual products. So, if I click on that particular coffee maker or that particular running shoe, you can see that the same type of information is presented in the same organization in both of these cases, even though there are different types of systems. So, we can see a picture of the item. We can see different pictures to look at different views of the item. We can scroll and see similar behavior for zooming in, in both cases. We see the ratings. We see the price and all of these things in the same organization. So, that if I've learned how to look for information about one type of product on Amazon, I can use that to look for other types of products and other information about those products even if they're completely different types of products. It's also important when designing a series or a suite of products to maintain consistency across those products, and we looked at this in an earlier lecture; but, for example, looking at the different Google apps for word processing and for spreadsheets, we see that a very similar layout is used for the menu bar and the formatting options. So, we see the same menus appear the same order: file, edit, view, insert, format and the same thing appears down here, and we see that similar formatting options are also visible right under the menu bar. This allows a user that's learned how to use one of these apps more rapidly learn how to use another app and gain productivity with that more quickly. As a result, it's often beneficial for competitors to borrow the design element of the design patterns from each other so that users who are switching to their product can more easily learn how to use those products. So, if we look at Microsoft Word Online, we see some of the same elements and some of the same arrangement. So, we see the menu here, slightly different options but we know where to look for those particular options, and we see formatting appear in the same place as it does in both of these products. Of course, I do realize that Microsoft Word came before Google Docs, but I think you get the point I'm trying to make. Finally, when looking at consistency and standards, it's important to follow platform standards or platform conventions wherever possible, unless you have a really good reason to do something differently. Let's look at a couple of examples of websites that don't follow platform conventions and not necessarily to a good effect. So, this is a website that sells a unique kind of housing called a flat pack house that can be rapidly constructed in lots of different environments, but their website doesn't follow standard web conventions for navigation. So, when looking at this, we can see that there's news in the center, but it's not clear where else you can go on this site. In order to figure that out, you actually need to hover over the numbers, and we see the navigation options now: what is FlatPack? How to FlatPack, and so on and so forth, and it doesn't necessarily get better when I click on one of these items. So, if I click on number two, how to flat pack, I'm also presented with an obscure difficult to read set of navigation options that I then need to go and further interact with in order to see what the options are. So, by deciding not to follow platform conventions, these website designers have created a system that's harder to use and harder to learn for somebody just coming to the system for the first time. While I was eventually able to figure it out, it wasn't clear or intuitive, and it presented a usability barrier to me and I presume to other people that would be coming to the site. Being consistent and complying with standards is very important when designing systems. We need to be consistent within the system, so across different parts of the system, consistent across different related systems and consistent with what users expect from interacting with other systems on the same platform, whether that's the web, or particular mobile operating system, or installed software. By being consistent, we can help users more rapidly learn to use the system that we're designing by taking advantage of what they've learned from using other similar systems in the past.