Response Time: Eight Seconds, Plus or Minus Two

People hate to wait.

You're the fourth person in a six-person line at the supermarket . You spot a clerk moving toward the closed register in the next lane. Is she going to open it? If you bail out too early and she's just looking for bags, it's the back of the line for you. Wait too long and the clerk could call over the next person in line. What do you do?

On the Internet, this kind of choice is simple. If the page you're waiting for takes more than a few seconds to open, you just bail out to another site. No bodies tojostle, no icy stares from the slower crowd . Just exercise your freedom of choice with a twitch of a finger. To hell with the owners of the slower site you just left. Survival of the fittest, right? It's all rosyunless, of course, you happen to be the owner of that slower site and it's a part of your business. In that case, it's a good thing you have this book.

In survey after survey, the most common complaint of Internet users is lack of speed. After waiting past a certain "attention threshold," users bail out to look for a faster site. Of course, exactly where that threshold is depends on many factors. How compelling is the experience? Is there effective feedback? This chapter explores the psychology of delay in order to discover why we are so impatient, and how fast is fast enough.

Lack of Speed Is the Most Common Complaint

Slow web sites are a universal phenomenon . Researchers have confirmed our need for speed in study after study:

• "GVU's Tenth World Wide Web User Survey," by Colleen Kehoe et al. (1999) http://www.gvu.gatech.edu/user_surveys/survey-1998-10/tenthreport.htmlOver half of those surveyed cited slow downloads as a problem.

• In "The Top Ten New Mistakes of Web Design" (1999) http://www.useit.com/alertbox/990530.htmlJakob Nielsen found that 84 percent of 20 prominent sites had slow download times.

• Designing Web Usability: The Practice of Simplicity by Jakob Nielsen (New Riders Publishing, 2000)"fast response times are the most important design criterion for web pages."

• In "System Response Time and User Satisfaction: An Experimental Study of Browser-based Applications," in Proceedings of the Association of Information Systems Americas Conference (2000), John Hoxmeier and Chris DiCesare found that user satisfaction is inversely related to response time. They said that response time "could be the single most important variable when it comes to user satisfaction."

The study of this psychology is called Human-Computer Interaction (HCI). This chapter focuses on the speed aspects of HCI. How does delay affect user satisfaction? Why do we become so frustrated when we have to wait? This chapter distills this research into understandable language and web page design guidelines.

Flow: The Compelling Experience

It's one thing to optimize a web site for speed and get satisfactory results. It's quite another to help your users achieve flow. Flow is an optimal state that is characterized by intense yet effortless concentration, a sense of being at one with a larger good, clarity of goals with challenges met, and actualization. Is it possible that optimal web design can lead to users experiencing this optimal state? You'll find out in Chapter 2, "Flow in Web Design."

With the rapid expansion of the web and increasing bandwidth, you would think that the problem of slow system response would have gone away. As you learned in the Introduction, the opposite is true: Consumer sites are actually becoming slower. ^[1] In fact, Zona estimates that over $25 billion in potential sales is lost online due to web performance issues. HCI research is just as relevant today as it was a decade ago.

^[1] Zona Research, "The Need for Speed II" [online], (Redwood City, CA: Zona Research, 2001 [cited 9 November 2002]), available from the Internet at http://www.keynote.com/downloads/Zona_Need_For_Speed.pdf. Found that although B2B sites have doubled their speed, consumer sites have become 20 percent slower.