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Branching Rules

Branching Rules

General concept

Branching is an advanced feature that allows the survey designer to create complicated questionnaires governed by a system of rules. In such surveys the questions may be asked in dependence upon the respondent's answers to the previous questions. This is achieved through the use of rules and logic operators. Such rule is a standard "if-then-else" construction which verifies whether a question (questions) is answered in a particular way and defines what questions are to be put next. Here is a typical branching rule:

If the question A is answered with the response A1, and the question B is not answered with the response B1, then go to the Page 3, else submit the survey.

Though it is possible to verify any question of the survey, movement is performed only within survey pages. A page is a section that contains one or more elements (questions, comments, or images) which are shown to the respondent on a separate HTML page. Hence, branching rules are applied to an entire page, not the separate questions inside it.

Another important point regarding branching rules is that they are processed after the page elements have been shown to the respondent. In other words, when you create branching, you define a set of rules that are verified and executed after the page is over. Consequently, branching rules applied to a particular page would not allow to define whether this page will be entered or not; it will be, in any case. Excluding pages from the survey may be performed by the branching rules at other pages, usually the preceding ones.

Below follow the description of particular elements and controls of the branching engine using the demonstration survey. This help chapter ends with the explanation of the results of the branching rules.

Branching elements

Check this box if you need to create conditions based on questions from previous pages. Normally, it is only available to verify questions of the current page. Enabling this option will allow you to use the preceding questions as well, thus taking them into account in your branching rules. In the example above, we verify that the respondent had answered 'Yes' to the question 'Do you possess a home computer?' which had been asked on a previous page.

 Add Rule  Click this button to add a new rule. This is the first button to click when you start creating rules.
In our example there are two rules, each verifying two conditions. The first one is:


This is the body of the condition. The first drop down box defines the question to verify, the second - verification type, and the third - the actual response. One condition checks one question against the following values:


• is NULL: the response is absent or not entered;
• is equal to: the response is as specified;
• is not NULL: the response exists - a mere fact of the response regardless of its content;
• is not equal to: the response is not as specified.

In our example, we check that the respondent had answered 'Yes' to the question 'Do you possess a home computer?'
Next follows the second condition:


This is another condition to be checked within the current rule. Any additional condition starts with the drop down box containing a logic operator. There are two of them:

• And: Both the current condition and the preceding one should be true;
• Or: Either the current condition, or the preceding one should be true.

Consequently, the first rule of our example is designed to check that the respondent has a home computer, and this computer is PC.

 Delete  Click this button to delete a condition.

 Add Condition  Click this button to add a new condition into the rule. There may be as many conditions inside a rule as you need.


Choose where to go in case the rule is considered true. In our example, if the respondent possesses a home computer and this computer is PC, the next question will be on Page 3. If any of these two conditions are false (e.g. he does not have a computer or it is not PC), the control passes to the next rule:


Next goes a similar rule with the only difference, that is 'Apple' instead of 'PC' in the second condition. Thus we check that the respondent has a computer, but it is of the Apple platform. If this is his case, the control goes to Page 4. If it is not, it means that he either does not has a computer, or has one of different architecture that is neither PC nor Apple. In this case the control goes to the third and the last rule:


Technically, this is also a rule, but a short one. It does not verify any conditions; all it does is passes the control to the specified destination, which in our case is the end of the survey.

 Save  Click this button to save the branching options and return to the 'Edit Survey' page.

 Cancel  Click this button to cancel all changes.

The Result of Branching Rules

What do we have as a result of these rules? There may be 4 possible scenarios of the survey, each with its own consequences:


1. The respondent does not have a home computer: In this case both the rules are considered false, the control is passed to the last "Go to" rule which submits the survey.
2. The respondent has a home computer, and it is PC: In this case Rule 1 is considered true and the control goes to Page 3, on which the respondent is asked about his PC manufacturer.
3. The respondent has a home computer, and it is Apple: In this case Rule 2 is considered true and the control goes to Page 4, where the respondent is asked about the type of his Apple computer.
4. The responded has a home computer, and it is neither PC, nor Apple: Technically, the result is the same as in case 1: both rules are considered false and the control goes to the last "Go to" rule which submits the whole survey. However, as was designated by the first question, the respondent could enter the architecture of his computer in a text comment field, so that we could get to know about it.

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