Editor’s note: Stefan Althoff is team manager, market research at Lufthansa Technik, a Hamburg, Germany, subsidiary of Lufthansa German Airlines. Bill MacElroy is president of Socratic Technologies Inc., a San Francisco research firm.

Why do people surf the Internet? Many go to hunt for information, to shop or do online banking. In the end, the search for entertainment - in the widest sense - is often most important. Online games or sites like YouTube are popular. To meet other people, even in a cyber sense, is another motivation. The value of entertainment extends to the ad realm, where ads that are perceived as funny are often judged to be more effective than those that don’t elicit laughs.

What motivates people to participate in a research study? A kind-looking interviewer at the front door, a well-dressed and polite mall researcher or a telephone interviewer with a pleasant voice can convince almost anyone to complete a survey.

Of course, this is different in the online market research world because of the self-administration aspect: The e-mail invitation and the questionnaire must motivate the potential participant. This is the same with registered online panel members: The registration in the panel and the general interview willingness are not enough.

Online research is becoming more and more popular worldwide as a channel for gathering market data and customer feedback. More than 50 percent of all interview projects in the U.S. are conducted online. Online research has lost the aura of novelty; therefore it is no surprise that response rates have dropped since its introduction in the mid-1990s. In addition, the number of people who start Web surveys only to abandon them midway has also grown significantly.

As a consequence, the main target in the analysis of non-response has shifted. In the past, the focus was on the interviewers and what they could do to increase response rates. ...