你可以學(xué)習(xí)的設(shè)計(jì)研究

In this lecture, we’re going to talk about trying out your interface with people and doing so in a way that you can improve your designs based on what you learned. One of the most common things that people ask when running studies is: “Do you like my interface?” and it’s a really natural thing to ask, because on some level it’s what we all want to know. But this is really problematic on a whole lot of levels.

我們這堂課要探討讓他人嘗試你的界面并根據(jù)所學(xué)內(nèi)容改進(jìn)設(shè)計(jì)的方法萍虽。在做研究時(shí)，有一個(gè)很常問的的問題是：『你喜歡我的界面嗎？』會問這個(gè)問題很正常鄙早，因?yàn)樵谀撤N程度上這確實(shí)是我們想知道的事酗昼。但在很大程度上這樣問反而會制造問題。

For one it’s not very specific, and so sometimes people are trying to make this better and so they’ll improve it by doing something like: “How much do you like my interface on one to five scale?” Or: “‘This is a useful interface’ — Agree or disagree on one to five scale.” And this adds some kind of a patina of scientificness to it but really it’s just the same thing — you’re asking somebody “Do you like my interface?” And people are nice, so they’re going to say “Sure I like your interface.” This is the “please the experimenter” bias. And this can be especially strong when there are social or cultural or power differences between the experimenter and the people that you’re trying out your interface with: For example, [inaudible] and colleague show this effect in India where this effect was exacerbated when the experimenter was white.

首先這不夠明確只洒，因此一些人進(jìn)行了改進(jìn)纵苛。他們會問諸如『以1-5作為程度劃分，你有多喜歡這個(gè)界面呢姻灶？』或者『從1-5為不同意至同意铛绰，這是個(gè)好用的界面，你同意嗎产喉？』這好像增加了一點(diǎn)科學(xué)感捂掰，但其實(shí)是一回事——你問別人『你喜歡我的界面嗎？』然后受訪者很友好地說『當(dāng)然曾沈，我喜歡你的界面这嚣。』這是『愉悅實(shí)驗(yàn)者』傾向塞俱。當(dāng)訪問者與受訪者有社會姐帚、文化或權(quán)力差異時(shí)，這個(gè)問題會更加嚴(yán)重：比如在印度我的同事就反饋了這個(gè)影響障涯，而且如果實(shí)驗(yàn)者是白人罐旗，影響會更加嚴(yán)重。

Now, you should not take this to mean that you shouldn’t have your developers try out stuff with users — Being the person who is both the developer and the person who is trying stuff out is incredible valuable. And one example I like a lot of this is Mike Krieger, one of the Instagram founders — [he] is also a former master student and TA of mine. And Mike, when he left Stanford and joined Silicon Valley, every Friday afternoon he would bring people into the lab into his office and have them try out whatever they were working on that week.

你不該用這個(gè)例子來說明開發(fā)者不應(yīng)讓用戶嘗試使用——如果用戶既是開發(fā)者又是嘗試者唯蝶，就會非常有價(jià)值九秀。有一個(gè)例子是Mike Krieger，instagram創(chuàng)始人之一——他曾是我的碩士學(xué)生及助教粘我。當(dāng)Mike離開斯坦福進(jìn)入硅谷時(shí)鼓蜒，每周五下午他會把人請入實(shí)驗(yàn)室辦公室，讓他們測試本周的工作成果征字。

And so that way they were able to get this regular feedback each week and the people who were building those systems got to see real people trying them out. This can be nails-on-a-chalkboard painful, but you’ll also learn a ton. So how do we get beyond “Do you like my interface?” The basic strategy that we’re going to talk about today is being able to use specific measures and concrete questions to be able to deliver meaningful results. One of the problems of “Do you like my interface?” is “Compared to what?”

用這種方法他們每周能獲得固定反饋都弹，而開發(fā)人員也能看到真實(shí)用戶使用產(chǎn)品。這個(gè)過程可能是極其痛苦的匙姜，但你也能學(xué)到很多畅厢。所以我們?nèi)绾尾拍軆?yōu)化『你喜歡我的界面嗎』這個(gè)問題呢？我們今天要講的基礎(chǔ)方法就是用明確測定和具象化問題的方法氮昧，以獲得有效結(jié)果框杜。『你喜歡我的界面嗎』中郭计，有一個(gè)問題是『和誰比』霸琴。

And I think one of the reasons people say “Yeah sure” is that there’s no comparison point and so one thing that’s really important is when you’re measuring the effectiveness of your interface, even informally, it’s really nice to have some kind of comparison. It’s also important think about, well, what’s the yardstick? What constitutes “good” in this arena? What are the measures that you’re going to use? So how can we get beyond “Do you like my interface?” One of the ways that we can start out is by asking a base rate question, like “What fraction of people click on the first link in a search results page?” Or “What fraction of students come to class?” Once we start to measure correlations things get even more interesting, like, “Is there a relationship between the time of day a class is offered and how many students attend it?”

我認(rèn)為人們會做肯定回答的一個(gè)原因是他們沒有比較物，因此要重視一件事昭伸，當(dāng)你測定頁面使用效率時(shí)梧乘，提供比較物非常有用。另一個(gè)重點(diǎn)是思考衡量標(biāo)準(zhǔn)是什么，在這個(gè)領(lǐng)域構(gòu)成『優(yōu)秀』的條件是什么选调，你打算測量什么數(shù)據(jù)夹供。所以我們應(yīng)該怎么改進(jìn)『你喜歡我的界面嗎』呢？其一仁堪，我們可以問一個(gè)基本比例問題哮洽，像『有多少比例的人在搜索結(jié)果界面會點(diǎn)擊第一條鏈接？』『有多少比例的學(xué)生會去上課弦聂？』一旦開始測量相互關(guān)系鸟辅，事情就變得更有趣了，像『上課時(shí)間和學(xué)生出勤率有關(guān)聯(lián)嗎莺葫？』

Or “Is there a relationship between the order of a search result and the clickthrough rate?” For both students and clickthrough, there can be multiple explanations. For example, if there are fewer students that attend early morning classes, is that a function of when students want to show up, or is that afunctionof when good professors want to teach? With the clickthrough example, there are also two kinds of explanations. If lower placed links yield fewer clicks, Is that because the links are of intrinsically poorer quality, or is it because people just click on the first link — [that] they don’t bother getting to the second one even if it might be better? To isolate the effect of placement and identifying it as playing a casual role, you’d need to isolate that as a variable by say, randomizing the order or search results.

或者『搜索結(jié)果順序與點(diǎn)閱率有關(guān)聯(lián)嗎匪凉？』學(xué)生和點(diǎn)閱率的例子都可以有很多解釋。比如捺檬，如果較少學(xué)生會出席清早的課堂再层，是否存在學(xué)生想準(zhǔn)時(shí)到場、或有好教授執(zhí)教這種應(yīng)變量呢堡纬？點(diǎn)閱率這個(gè)例子也有兩種解釋聂受。如果位置較低的鏈接點(diǎn)閱率少，是否有可能是鏈接本身質(zhì)量低下烤镐？還是因?yàn)槿藗冎稽c(diǎn)擊第一個(gè)鏈接——他們不在乎點(diǎn)不點(diǎn)第二個(gè)鏈接蛋济，即使它更好呢？為了分離位置的影響并把它定義原因职车，你需要把它分離為變量瘫俊，使順序和搜索結(jié)果隨機(jī)化鹊杖。

As we start to talk about these experiments, let’s introduce a few terms that are going to help us. The multiple different conditions that we try, that’s the thing we are manipulating — for example, the time of a class, or the location of a particular link on a search results page. These manipulations are independent variables because they are independent of what the user does. They are in the control of the experimenter. Then we are going to measure what the user does and those measures are called dependent variables because they depend on what the user does.

為討論這些實(shí)驗(yàn)悴灵，讓我引入一些術(shù)語來幫助陳述。我們嘗試的許多不同條件是我們的實(shí)驗(yàn)操縱——比如上課時(shí)間骂蓖、搜索頁面中特定鏈接的位置积瞒。這些實(shí)驗(yàn)操縱是自變量，因?yàn)樗麄兒陀脩粜袨闆]關(guān)系登下。它們由實(shí)驗(yàn)者操縱茫孔。然后我們就會測量用戶做什么，而這些測量就是因變量被芳，因?yàn)樗鼈冸S用戶行為變化缰贝。

Common measures in HCI include things like task completion time — How long does it take somebody to complete a task (for example, find something I want to buy, create a new account, order an item)? Accuracy — How many mistakes did people make, and were those fatal errors or were those things that they were able to quickly recover from? Recall — How much does a person remember afterward, or after periods of non-use? And emotional response — How does the person feel about the tasks being completed? Were they confident, were they stressed? Would the user recommend this system to a friend? So, your independent variables are the things that you manipulate, your dependent variables are the things that you measure.

HCI的慣常測量項(xiàng)目包括完成時(shí)間——人們完成一個(gè)任務(wù)要多久（比如找一個(gè)我要買的東西，創(chuàng)建一個(gè)新賬號畔濒，點(diǎn)一份東西）剩晴；精確度——用戶犯了幾個(gè)錯(cuò)，這些是致命錯(cuò)誤還是能快速恢復(fù)正常的問題；回憶——使用結(jié)束后赞弥、或一段時(shí)間不用后用戶還記得多少毅整；還有情感反饋——當(dāng)任務(wù)完成后用戶有什么感受？他們很有自信還是很沮喪绽左？用戶會把這個(gè)系統(tǒng)推薦給朋友嗎悼嫉？因此，你的自變量是你操縱的因素拼窥，你的因變量是你測量的因素戏蔑。

How reliable is your experiment? If you ran this again, would you see the same results? That’s the internal validity of an experiment. So, have apreciseexperiment, you need to better remove theconfoundingfactors. Also, it’s important to study enough people so that the result is unlikely to have been by chance. You may be able to run the same study over and over and get the same results but it may not matter in some real-world sense and the external validity is thegeneralizabilityof your results. Does this apply only to eighteen-year-olds in a college classroom? Or does this apply to everybody in the world? Let’s bring this back to HCI and talk about one of the problems you’re likely to face as a designer. I think one of the things that we commonly want to be able to do is to be able to ask something like “Is my cool new approach better than the industry standard?” Because after all, that’s why you’re making the new thing.

你的實(shí)驗(yàn)有多可靠？如果你再做一次會得到相同結(jié)果嗎鲁纠？這是實(shí)驗(yàn)的內(nèi)部效度辛臊。因此，為了有一個(gè)明確實(shí)驗(yàn)房交，你需要除去混淆因素彻舰。此外，調(diào)查足夠多的用戶也非常重要候味，這樣結(jié)果比較準(zhǔn)確刃唤。你可能重復(fù)做同一個(gè)研究得到相同結(jié)果，但該研究在現(xiàn)實(shí)世界卻失效了白群，外部效度就是結(jié)果的普適性尚胞。這個(gè)研究是否只適用于大學(xué)課堂十八歲的學(xué)生還是適用于每個(gè)人？讓我們把話題重返HCI并探討作為設(shè)計(jì)師的你可能會面臨的一個(gè)問題帜慢。我們通常希望能問諸如『我這個(gè)酷炫的創(chuàng)新是否優(yōu)于行業(yè)標(biāo)準(zhǔn)笼裳？』這種問題，畢竟這是我們想創(chuàng)新的原因粱玲。

Now, one of the challenges with this, especially early on in the design process is that you may have something which is very much in its prototype stages and something that is the industry standard is likely to benefit from years and years of refinement. And at the same time, it may be stuck with years and years ofcruftwhich may or may not be intrinsic to its approach. So if you compare your cool new tool to some industry standard, there is two things varying here. One is the fidelity of the implementation and the other one of course is the approach. Consequently, when you get the results, you can’t know whether to attribute the results to fidelity or approach or some combination of the two. So we’re going to talk about ways ofteasingapart those differentcausal factors. Now, one thing I should sayright off the batis there are some times where it may be more or less relevant whether you have a good handle on what the causal factors are.

此時(shí)這里有一個(gè)挑戰(zhàn)（尤其在設(shè)計(jì)過程初期）在于你的設(shè)計(jì)完全處于原型階段躬柬，而行業(yè)標(biāo)準(zhǔn)已經(jīng)過長期改進(jìn)。與此同時(shí)抽减，行業(yè)標(biāo)準(zhǔn)也長期裹挾冗余部分允青，變得不太純粹。當(dāng)你比較你的新創(chuàng)造和行業(yè)標(biāo)準(zhǔn)時(shí)卵沉，有兩件事不太相同颠锉。一是實(shí)現(xiàn)的精確度，二是方法史汗。因此琼掠，當(dāng)你獲得結(jié)果時(shí)，你無法知道到底把結(jié)果歸因于精度還是方法或它們的結(jié)合停撞。所以我們來探討一下梳理不同起因的方法〈赏埽現(xiàn)在我馬上想說的是，不同時(shí)間對你是否很好掌握什么是起因有或多或少的關(guān)系。

So for example, if you’re trying to decide between two different digital cameras, at the end of the day, maybe all you care about is image quality or usability or some other factor and exactly what makes that image quality better or worse or any other element along the way may be less relevant to you. If you don’t have control over the variables, then identifying cause may not always be what you want. But when you are a designer, you do have control over the variables, and that’s when it is really important toascertaincause. Here’s an example of a study that came out right when the iPhone was released, done by a research firm User Centric, and I’m going to read from this news article here. Research firm User Centric has released a study that tries togaugehow effective the iPhone’s unusual onscreen keyboard is. The goal is certainly a noble one but I cannot say the survey’s approach results in data that makes much sense.

比如速挑，如果你想從兩款不同的數(shù)碼相機(jī)中選擇谤牡，在最后一天你可能就只關(guān)心成像質(zhì)量、易用性或其他因素姥宝，而真正影響照片質(zhì)量的因素就沒那么有相關(guān)性了翅萤。如果不控制變量，那么得出的成因就可能不是你想要的腊满。當(dāng)你是設(shè)計(jì)師時(shí)套么，嚴(yán)謹(jǐn)控制變量時(shí)就是確定成因的重要時(shí)刻。這里有一個(gè)iPhone剛發(fā)布時(shí)產(chǎn)出的研究實(shí)例碳蛋，由研究機(jī)構(gòu)User Centric完成胚泌。我想在這兒讀一下這篇新聞。User Centric發(fā)布了一項(xiàng)研究來測量iPhone這塊屏顯鍵盤的使用效率肃弟。文章的目的很崇高玷室，但我不能說這個(gè)研究很有效。

User Centric brought in twenty owners of other phones. Half had qwerty keyboards, half had ordinary numeric phones, withkeypads. None were familiar with the iPhone. The research involved having the test subjects enter six sample test messages with the phones that they already had, and six with the iPhone. The end result was that the iPhonenewbiestook twice as long to enter text with an iPhone as they did with their own phones and made lots more typos. So let’s critique this study and talk about its benefits and drawbacks. Here’s the webpage directly from User Centric. What’s our manipulation in this study? Well the manipulation is going to be the input style. How about the measure in the study? It’s going to be the words per minute. And there’s absolutely value in being able to measure the initial usability of the iPhone.

User Centric引入了20位其他手機(jī)用戶笤受。他們一半人使用全鍵盤穷缤，一半人使用手機(jī)按鍵的數(shù)字鍵盤，沒人熟悉iPhone箩兽。這個(gè)研究讓測試者用現(xiàn)有的手機(jī)發(fā)送六條簡短短信津肛，再用iPhone發(fā)一遍。研究結(jié)果是這些iPhone新手們使用iPhone的耗時(shí)是現(xiàn)有手機(jī)的兩倍汗贫，而且還產(chǎn)生了更多錯(cuò)誤身坐。讓我們來評判下這個(gè)研究的優(yōu)缺點(diǎn)。這是User Centric的網(wǎng)頁落包。在這個(gè)實(shí)驗(yàn)中部蛇，實(shí)驗(yàn)操縱是什么？實(shí)驗(yàn)操縱應(yīng)該是輸入方式妥色。實(shí)驗(yàn)的測量是什么搪花？應(yīng)該是每分鐘產(chǎn)出的字?jǐn)?shù)遏片。在這里氓皱，測量iPhone的初始易用度當(dāng)然很有價(jià)值涝影。

For several reasons, one is if you’re introducing new technology, it’s beneficial if people are able to get up to speed pretty quickly. However it’s important to realize that this comparison is intrinsically unfair because the users of the previous cell phones were experts at that inputmodalityand the people who are using the iphone are novices in that modality. And so it seems quite likely that the iPhone users, once they become actual users, are going to get better over time and so if you’re not used to something the first time you try it, that may not be a deal killer, and it’s certainly not anapples-to-apples comparison. Another thing that we don’t get out of this article is “Is this difference significant?” So we read that each person who typed six messages in each of two conditions and so they did their own device and the iPhone, or vice versa.

有幾個(gè)原因，第一，如果你引入新技術(shù)封孙，人們?nèi)绻芎芸焓炀氉匀皇呛芎玫模覀円庾R到這個(gè)比較并不公平缝裤。因?yàn)橛脩艟▊鹘y(tǒng)手機(jī)的輸入方法肉渴，而他們在iPhone上卻是新手。因此很有可能的是，iPhone用戶變成日常用戶后微渠，他們的表現(xiàn)就會更好搭幻。而且如果你第一次嘗試某個(gè)事物不太習(xí)慣，這可能并不是大問題逞盆。而且這完全不是一個(gè)同類比較檀蹋。第二，文章并沒指出『這個(gè)不同重要嗎云芦？』因此我們只能知道每個(gè)人用自己的設(shè)備和iPhone分別輸入了六條短信而已俯逾。

Six messages each and that the iPhone users were half the speed of the… or rather the people typing with the iPhone were half as fast as when they got to type with a mini qwerty at the device that they were accustomed to. So while this may tell us something about the initial usability of the iPhone, in terms of the long-term usability, you know, I don’t think we get so much out of this here. If you weren’t satisfied by that initial data, you’rein good company: neither were the authors of that study. So they went back a month later and they ran another study where they brought in 40 new people to the lab who were either iPhone users, qwerty users, or nine key users. And now it’s more of an apples-to-apples comparison in that they are going to test people that are relatively experts in these three differentmodalities— after about a month on the iPhone you’re probably starting toasymptotein terms of your performance.

每人發(fā)六條短信，然后iPhone用戶速度是一半…或者說iPhone用戶的輸入速度是使用熟悉的全鍵盤用戶輸入速度的一半舅逸。這個(gè)調(diào)查展示了iPhone的初始易用度桌肴，但從長遠(yuǎn)角度考察易用性，我并不覺得這篇調(diào)查幫助很大琉历。如果你不滿意這個(gè)初始數(shù)據(jù)坠七，你有同伴了：這份研究的作者也并不滿意。于是一個(gè)月后他們又做了一次研究旗笔，邀請40位使用iPhone灼捂、全鍵盤及九宮格的用戶。這次比較更趨向同類比較了换团，因?yàn)檫@些用戶都是他們輸入方式的專業(yè)用戶了——在使用一個(gè)月后悉稠，你開始能根據(jù)表線畫漸近線了。

Definitely it gets better over time, even past a month; but, you know, a month starts to get more reasonable. And what they found was that iPhone users and qwerty users were about the same in terms of speed, and that the numeric keypad users were much slower. So once again our manipulation is going to be input style and we’re going to measure speed. This time we’re also going to measure error rate. And what we see is that iPhone users and qwerty users are essentially the same speed. However, the iPhone users make many more errors. Now, one thing I should point out about the study is that each of the different devices was used by a different group of people. And it was done this way so that each device was used by somebody who is comfortable and had experience with working with that device. And so, we removed the worry that you had newbies working on these devices.

當(dāng)然艘包，在一段時(shí)間后使用表現(xiàn)肯定會好的猛，即使只是一個(gè)月；但一個(gè)月的時(shí)間開始變合理了想虎。研究人員發(fā)現(xiàn)iPhone用戶和全鍵盤用戶在速度上基本持平卦尊，而九宮格用戶明顯慢。所以這次我們的實(shí)驗(yàn)操縱是輸入方式舌厨，測量是速度岂却。這次也要測量出錯(cuò)率。我們看到iPhone用戶和全鍵盤用戶輸入速度本質(zhì)相同裙椭。但是躏哩，iPhone用戶出錯(cuò)率更高。這次我要指出的是揉燃，不同設(shè)備是由不同人群使用的扫尺。因此設(shè)備使用者都符合習(xí)慣并有使用經(jīng)驗(yàn)。我們就移除了新手使用設(shè)備的問題炊汤。

However, especially in 2007, there may have been significant differences in who the people were who were using theearly adoptersof the 2007 iPhone or maybe business users were particularly drawn to the qwerty devices or people who had better things to do with their time than send e-mail on their telephone or using the nine key devices. And so, while this comparison is better than the previous one, the potential for variation between the user populations is still problematic. If what you’d like to be able to claim is something about the intrinsic properties of the device, it may at least in part have to do with the users. So, what are some strategies for fairer comparison? To brainstorm a couple of options one thing that you can do is insert your approach in to your production setting and this may seem like a lot of work — sometimes it is but in the age of the web this is a lot easier than it used to be.

然而正驻，尤其在2007年弊攘，用戶群發(fā)生了巨大改變。2007版iPhone的首批用戶是誰姑曙？又或者商務(wù)用戶被全鍵盤設(shè)備深深吸引,除了在手機(jī)上發(fā)郵件襟交，用戶可能有更有意思的事可做，九宮格用戶也是如此伤靠。所以婿着，雖然他們這次的對比比之前的好，但用戶群體的潛在變化也會制造問題醋界。如果你想說的是一個(gè)設(shè)備的本質(zhì)特性竟宋，那它至少和用戶有一部分關(guān)系。所以更公平的比較方法是什么呢形纺？為了發(fā)掘多項(xiàng)選擇丘侠，你可以把你的方法放入生產(chǎn)設(shè)定，這工程量很大——在web時(shí)代可能會比以前容易些逐样。

And it’s possible even if you don’t have access to the server of the service that you’re comparing against. You can use things like aproxy serveror client-side scripting to be able to put your own technique in and have an apples-to-apples comparison. A second strategy forneutralizingthe environment difference between a production version and your new approach is to make a version of the production thing in the same style as your new approach. That also makes them equivalent in terms of their implementation fidelity. A third strategy and one that’s used commonly in research, is toscale things downso you’re looking at just a piece of the system at a particular point in time. That way you don’t have to worry about implementing a whole big, giant thing. You can just focus on one small piece and have that comparison be fair.

即使你無法接入對比服務(wù)的服務(wù)器蜗字，這也是有可能的。你可以把自己的技術(shù)放入代理服務(wù)器或客戶端腳本脂新，使同類比較成為可能挪捕。第二個(gè)解決生產(chǎn)版本和你的新技術(shù)的環(huán)境差異的策略是用你的新技術(shù)做同樣的生產(chǎn)版本。這樣就統(tǒng)一了實(shí)現(xiàn)精度争便。第三個(gè)在研究中也很常用的策略是縮小規(guī)模级零，這樣你只是考察系統(tǒng)某一部分的某一特定點(diǎn)。這個(gè)方法使得你不用去看產(chǎn)品的宏觀實(shí)施滞乙。你可以縮小范圍奏纪，使比較更公平。

And the fourth strategy is that when expertise is relevant, train people up — give them the practice that they need —, so that they can start at least hitting that asymptote in terms of performance and you can get a better read than what they would be as newbies. So now to close out this lecture, if somebody asks you the question “Is interface x better than interface y?” you know that we’re off to a good start because we have a comparison. However, you also know to be worried: What does “better” mean? And often, in a complex system, you’re going to have several measures. That’s totally cool. There’s a lot of value in beingexplicitthough about what it is you mean by better — What are you trying to accomplish? What are you trying to [im]prove? And if anybody ever tells you that their interface is always better, don’t believe them because nearly all of the time the answer is going to be “it depends.”

第四個(gè)策略是斩启，當(dāng)熟練度相關(guān)時(shí)序调，訓(xùn)練被實(shí)驗(yàn)者——讓他們獲得需要的鍛煉——這樣他們起碼能達(dá)到表現(xiàn)曲線，他們能比作為新手時(shí)得到更好的解讀⊥么兀現(xiàn)在結(jié)束這次講課发绢，如果有人問你『界面X是否比界面Y更好？』時(shí)垄琐，你要知道由于存在比較边酒，我們擁有了一個(gè)很好的開端。但是你也要知道有這樣一個(gè)問題：什么叫『更好』此虑？通常在復(fù)雜的系統(tǒng)中甚纲，你有很多東西要測量。這太酷了朦前。明確更好的含義有巨大價(jià)值——你想達(dá)成什么介杆？你想改進(jìn)什么？如果有人跟你說他們的界面永遠(yuǎn)更好韭寸，別信他們春哨，因?yàn)榛旧纤袝r(shí)候這個(gè)回答都應(yīng)該是『看情況』。

And the interesting question is “What does it depend on?” Most interfaces are good for some things and not for others. For example if you have a c computer where all of the screen is devoted to display, that is going to be great for reading, for web browsing, for that kind of activity, looking at pictures. Not so good if you want to type a novel. So here, we’ve introduced controlled comparison as a way of finding thesmoking gun, as a way of inferring cause. And often for, when you have only two conditions, we’re going to talk about that as being a minimal pairs design. As apracticing designer, the reason to care about what’s causal is that it gives you the material to make a better decision going forward. A lot of studies violate this constraint. And, that gets dangerous because it doesn’t, it prevents you from being able tomake sound decisions. I hope that the tools that we’ve talked about today and in the next several lectures will help you become a wiseskepticlike our friend in this XKCD comic. I’ll see you next time.

一個(gè)有趣的問題是『看什么情況恩伺？』許多界面只適配某一些情況赴背。比如你的平板電腦完全用來顯示，對于閱讀晶渠、網(wǎng)頁瀏覽或看圖這類活動非常適用凰荚，但就不適用于寫小說。所以在這里我們引入控制變量比較法找到確切的證據(jù)推斷原因褒脯。而且通常便瑟，當(dāng)你只有兩種條件時(shí)，我們像最小組設(shè)計(jì)一樣談?wù)撍鼈兎āＷ鳛橐晃辉诠ぷ鞯脑O(shè)計(jì)師到涂，關(guān)注什么是原因是因?yàn)檫@能給你做更好決定的材料。許多研究違反了這一限制颁督。這很危險(xiǎn)践啄。它會讓你無法做出可靠的決定。我希望今天課程所授能幫助你成為一個(gè)明智的懷疑論者沉御，像XKCD漫畫上的這位朋友屿讽。下次見。