Answered => “Online Surveys: What is the major challenge for people running online surveys?” on Quora.

http://www.quora.com/Online-Surveys/What-is-the-major-challenge-for-people-running-online-surveys

=> My answer…

All good answers thus far. Let me spare you the duplication and just try to fill another gap.

It’s important to understand that the data you collect is based on (read: limited to) those who answered the survey. Even if you have a large enough data set there’s still the potential for bias in who filled it out end to end.

Perhaps that’s stating the obvious but we’ve all seen plenty of instances where statistical results are taking for universal gospel. In other words, when presenting the results at the top of every page it should say, “Of the people who responded to our survey and completed it.” Those people might not be the same as your ideal.