You can achieve a high-quality user interface by combining 3 design process models:

  1. 竞争测试
  2. Parallel design
  3. 迭代设计

Although you should apply the methods in the above list's sequence, I'll discuss them in the opposite order here.

所有3种方法都有一个基本的想法:有没有一个完美的用户界面设计,通过简单地运送您的一个最佳主意,您无法获得良好的可用性。你必须try (and test) multiple design ideas。Competitive, parallel, and iterative testing are simply 3 different ways to consider design alternatives. By combining them, you get wide diversity at a lower cost than simply sticking to a single approach.

Iterative Design

I start with iterative design here because it's the

  • simplest过程模型(线性进展);
  • 最老的foundation for user-centered design (UCD),
  • 最便宜的(you often can iterate in a few hours); and
  • strongest那because you can keep going for as many iterations as your budget allows (competitive and parallel testing are usually one-shot components of a design project).

我几乎不需要define iterative design: I wrote a long paper about it 18 years ago, and it hasn't changed:

Iterative user interface design: conceptual process model

Iteration simply means to step through one design version after another. For each version, you conduct a usability evaluation (such asuser testing或者启发式评价)和基于这些usabi修改下一个版本lity findings.

How Many Iterations?

I recommend至少2个迭代。这2个迭代对应于3个版本:第一次草稿设计(我们所知道的是不够好的),然后是2个重新设计。但我的偏好是5–10 iterations或更多,特别是何时每周迭代(甚至更常见)。

Of course, one iteration (that is, a single redesign, for a total of 2 design versions) is still better thanshipping your best guesswithout usability-derived improvements. But experience shows that the first redesign will have many remaining usability problems, which is why it's best to plan for at least 2 iterations.

更多的迭代更好: I've never seen anyone iterate so much that there were no usability improvements to be had from the last iterations. In my research 18 years ago,测量的可用性每个迭代的38%提高了38%。这些指标来自传统的应用程序发展;如果我们查看网站,则改进通常更大。在较新的案例研究中,目标KPI改善了233%across 6 iterations(7个设计版本=版本之间的6个迭代),对应每次迭代22%。The key lesson from this latter case study is that it's best to keep iterating, because you can keep piling on the gains.

To get many iterations within a limited budget and timeline, you can usediscount usabilitymethods: createpaper prototypesfor the early design versions, planning about 1 day per iteration. In later versions, you can graduallyproceed to higher-fidelityrenderings of the user interface, but there's no reason to worry about fine details of the graphics in early stages, when you're likely to rip the entire workflow apart between versions.

Simple user testing(5 users or less) will suffice, because you'll conduct additional testing for later iterations.

Limitations of Iterative Design?


My main comeback?“所以呢。”绝大多数用户界面设计项目是行人尝试制作e-commerce site, 一个employee directory,或一些类似的大规模numbe特性r ofwell-documented best practices

是的,一些设计问题是根本性的 - 例如iPad或Kinect的原始设计。有些是半自由基,如设计第一代iPad应用程序或者Kinect game(在平台本身已经设计后,但在记录了相应的可用性指南之前)。但大多数设计问题都属于具有众多现有设计的类别。

Of course, superior solutions that exceed current best practice are possible; after all, we haven't seen the perfect user interface yet. But most designers would be happy to nearly他们的商业指标。简单地通过迭代设计抛光设计的可用性非常高ROI,通常优于更高的收益所需的投资。


Although I remain a strong fan of iterative design, it's true that it limits us to improving a single solution. If you start out in the wrong part of the design space, you might not end up where you'd really like to go.


Parallel user interface design: conceptual process model

In a parallel design process, you createmultiple alternative designsat the same time. You can do this either by encouraging a single designer to really push their creativity or by assigning different design directions to different designers, each of whom makes one draft design.

In any case, to stay within a reasonable budget, all parallel versions should be created quickly and cheaply. They don't need to embody a complete design of all features and pages. Instead, for a website or intranet, you can design maybe 10 key pages and, for an application, you can design just the top features. Ideally, you should spend just a few days designing each version and refine them only to the level of rough wireframes.

Although you should create a minimum of3 different design alternatives,这不值得设计更多。5可能是最大值。


用户测试后,创建单个合并的设计那taking the best ideas from each of the parallel versions. The usability study is not a competition to identify "a winner" from the parallel designs. Each design always has some good parts and some that don't hold up to the harsh light of user testing.

最后,proceed with iterative design(如上所述)进一步改进合并的设计。

15 years ago I conducted aresearch study of parallel design,我们尝试并评估了3种不同的替代方案:

  • 用4个并行版本,简单pick the best one并迭代它。这种方法导致了测量的可用性56%更高比原始4个设计的平均值。
  • 遵循推荐的流程和use a merged design那instead of picking a winner. Here, measured usability was70%更高,给我们额外的14%收益,包括“失败”设计的最佳思路。
  • 继续迭代from the merged design. After one iteration, measured usability was152%更高比原始设计的平均值。(所以,一个额外的迭代增加了48%usability to the merged design — calculated as 2.52/1.70. This is within the expected range of gains from iterative design.)


My study was in the domain of traditional application development. In arecent study那Steven P. Dow and his colleagues from Stanford University took this approach to the domain of Internet advertising. For the Stanford study, a group of designers created banner advertisements for a social media site, aiming to optimize the click-through rate (CTR). Ads created through a parallel design process achieved 0.055% CTR, whereas ads created without parallel design achieved 0.033% CTR. So,平行设计更好地进行了67%。They recorded these scores over the前5天广告活动。

Over the full15天的竞选活动那parallel-design ads scored 0.045% CTR compared with 0.040% CTR for nonparallel-design ads. Over this longer campaign, parallel design was only12%更好

We've long known that people tend toscreen out Web ads。This might imply that it's best to constantly launch new ads and run very short campaigns with each, though I'd like to see more data before forming a firm conclusion on this point.

So, even though the conclusions are less strong for ads than for apps, the bottom line is the same: parallel design generates better outcomes.

(Learn more about parallel design in our full-dayEffective Ideation Techniques for UX Designcourse.)


In a competitive usability study, youtest your own design and 3–4 other companies' designs。The process modellooks the same as for parallel design,除了原始设计替代品是预先存在的网站或应用程序,而不是您为研究专门创建的线框。

The benefit of competitive testing is also the same as for parallel design: you gain insight into user behaviors with a broad range of design options before you commit to a design that you'll refine through iterative design.

竞争测试is also advantageous in that you don't spend resources creating early design alternatives: you simply pick from among the ones available on the Web (assuming you're doing a website; competitive testing doesn't work for intranets and other domains where you can't easily get your hands on other companies' designs.)

就像并行设计一样,竞争测试不应该简单地成为涂抹“赢家”的基准。当然,它可以让大多数公司的竞争果汁炖,了解讨厌的竞争对手分数,比如,在关键可用性指标上增加了45%。这些数字可以刺激执行行动。但一如既往,quantitative measurements provide weaker insightsthan qualitative research. A more profitable goal for competitive studies is to understandwhy and how用户behave在某些方面;了解他们的功能like或者find confusing across a range of currently popular designs; and discover opportunities to serveunmet needs

Many design teams skip competitive testing because of the added expense of testing several sites. (For example, Nielsen Norman Group目前收费$45,000 for most competitive testing and only $22,000 to test a single website. Of course, you can get cheaper tests from Tier-2 or Tier-3 usability firms, but they'll still charge more for bigger studies.) But this step is well worth the cost because it's the best way to深入了解用户需求在您尝试设计某些东西以满足这些需求之前。

竞争测试is particularly important if you're using an敏捷development methodology因为在单个冲刺期间,您往往没有时间更深入的探索。您可以在开始开发项目之前进行竞争性研究,因为您正在测试现有网站而不是新设计。当您需要在Sprint期间进行快速决策时,您可以稍后返回洞察力。从项目前竞争测试的见解,因此作为银行的金钱,您可以在挤压时退出。


所有3个方法 - 迭代,平行和竞争 - 有争议的原因:而不是限于你最好的主意尝试一系列设计并且实际上看到了哪些与您的客户合作in user testing.


In the ideal process, you'd first conduct competitive testing to get deep insights into user needs and behaviors with the class of functionality you're designing. Next, you'd proceed to parallel design to explore a wide range of solutions to this design problem. Finally, you'd go through many rounds of iterative design to polish your chosen solution to a high level of user experience quality. And, at each step, you should be sure to根据经验观察判断设计of real用户行为而不是您自己的偏好。(在我之后重复:“我不是观众。”