Skip Logic & Conditional Branches in Surveys

Survey respondents can be routed through questionnaires using three types of branching logic:

• Skipping specific questions: A skip pattern will jump a respondent over a group of questions that isn't relevant to them. For instance, a common skip pattern has a respondent rate a particular attribute on a scale and, if the rating is high, skips the respondent over one or two follow-up questions designed to probe why other respondents gave the item a low rating.
• Conditional branching: A branch pattern will route a respondent to the appropriate section of the questionnaire: each respondent follows one of the branches. A common branch pattern has a respondent classify a product purchase or a type of service interaction and then asks follow-up questions specific to that answer.
• Unconditional destination: Often a branching pattern is terminated with an unconditional destination, which returns respondents back to a common path. This has the effect of jumping respondents over other branches.

When you find yourself writing a question that starts with something like "If you answered ‘No' to the previous question", that is a sure sign that you should set up a skip or branch pattern. Making people do this logic in their head is fine in a paper survey, but it is in appropriate for online surveys. Such manual skip patterns slow down the respondent, increase the amount of reading that they must do and make completing the survey tedious. Conversely, when skip and branching patterns are well implemented, they make the survey highly relevant and engaging.
A great example of well-implemented branching is a web-site feedback survey created by one Vovici client. With over 15 million unique visitors a month to their web site, the client determined that visitors typically came to the site with one of 17 different purposes in mind. Visitors to the site were randomly invited to take the feedback survey, which began with five standard questions that all respondents were asked, ending with a question asking "So what are you here to do today?" The answer to this gating question would then branch respondents to one of 17 different paths, each asking an average of 8 questions unique to that action. The result was that no respondent answered more than 20 questions of a 148-question survey, and the questions they did answer were very specific to their experience.
Your own skip and branching patterns don't need to be as complex. Some best practices for skip and branching logic:

• Remember that page breaks indicate logical jumping-off points. Sometimes survey authors like to have one question per page; other authors like to have related questions together on a page. Skip logic overrides the preference for how to group questions, as it is only applied at the end of a page.
• Skip logic routes respondents forward through the survey, never backward. Think of the question flow like a river, going downstream, with different sluice gates channeling the water into different canals and sometimes back into the main watercourse.
• Due to the wide variety of possible synonymous answers to open-ended questions, skip logic is primarily used with closed-ended questions.
• Before inviting respondents to take your survey, make sure you test that each path through the survey matches the logic you intended.
• Some survey software applications, include Vovici v4, support Boolean logic ("and", "or" and "not" and nested parentheses). This makes programmers happy, but can be confusing for first-time survey authors. For instance, "and" doesn't have its English meaning: a survey author who wants the system to skip to Q9 when Q1 is answered "blue" and "green" needs to write "Q1=blue or Q1=green" not "Q1=blue and Q1=green" (which is a logical impossibility from a Boolean perspective). If you are using advanced branching for the first time, get some help from technical support or a programmer and test your survey logic carefully.
• For a questionnaire already collecting responses, you sometimes might find that you should have added a skip pattern. Good survey software will let you do this, then provide a utility to validate all previous answers against this new skip pattern, setting any answers back to unanswered for questions that shouldn't have been asked.
• If you are displaying progress bars, respondents may suddenly find themselves very far through the survey, because of a skip pattern. Curious respondents may hit the Back button, then answer differently to see where they go next. Respondents are more likely to do this in the screener if the survey offers a financial incentive to qualifying respondents. In such cases, configure the survey to not publish a Back button beside the Next button.

What other best practices do you follow when using skip logic?