Block

Block nodes are elements that enable you to group questions and other items together such that the grouped items can be processed specially or separately within the survey. Several types of Block element are available in :

• The Block element within the survey - enables you to group questions together and apply for example randomization or rotation to the questions within the block. This is standard survey functionality that is used frequently in market research to avoid bias in responses, which can arise as a result of the order in which the questions are presented. Add questions and nodes to the block by clicking the + Inside button above or below the overlay; the new item is added at the bottom of the block's contents below any existing items. In addition to normal questions, Blocks can contain complex structures such as conditions and loops, and it is also possible to nest Blocks. The Blocks will have single page breaks.

Figure 1 - The Block node’s details page

• The Call blocks folder in the Survey pane - allows you to set up groups of questions outside of the survey, and call these blocks when they are required. Click the Call blocks icon to open the Call blocks pane. The pane contains a Start block and an End block as default (see below for details), and you can add any number of call blocks to the pane by clicking the green + Call block before/after buttons as required. Call blocks are then called to the survey by Block to call nodes (go to Block to Call for more information).

Figure 2 - The Call Blocks folder

• Call blocks are similar to the blocks described above and are intended to contain individual questions or sets of questions, but they are not part of the standard survey. This means that these blocks and their contents will not be executed automatically when a respondent answers the survey, but must be activated by a Call block item placed in the survey. When the respondent works their way through the survey and they come to a Call block item, the Call block will divert the survey flow to the specified block. Once the contents of the block have been processed, the survey will return automatically to the point immediately after the Call block, and the survey will continue. Any number of Call blocks can be added to the survey. These can be called at any time during the survey, and the same block can be executed any number of times by different Block To Call nodes in the survey. For the questions inside the block, any answers entered during previous executions of the block will remain. The Block To Call nodes can themselves be activated by for example scripting within other questions in the survey.

Note: The use of scripted Redirect() to jump into or out of questions that are in Call blocks will cause problems and should not be attempted. A key attribute of Call blocks is that they can be entered from multiple points in a survey (see above), so the survey engine will not have a specific “entry-point” that has been used to enter that Call block. Therefore when the Call block finishes it does not know where in the main body of the survey to return to, and the survey will simply error.

Note: Loop reference variables are not supported in callblocks.

• A Start block is a special type of block that will ALWAYS be activated at the beginning of a survey. Any questions or other items located within the Start block will always be the first things that are processed when the respondent starts the survey. The Start block will be presented to the respondent whenever he/she enters the survey for first time, and whenever the respondent returns to the survey after a postponement unless the option "Allow respondents to change their original answers" is disabled. On returning to the survey, the Start block will present the answers that the respondent has entered previously, and the respondent can then change those answers as required. A Start block cannot be deleted from the survey. If no questions are added to the Start block, then it will be ignored.
• An End block is a special case block that will ALWAYS be activated at the end of a survey. Any questions or other items located within the End block will always be the last things that are processed when the respondent completes the survey. The questions contained within the End block will be presented to the respondent whenever he/she leaves the survey, either due to postponement or because the survey is completed. If the respondent returns to the survey later, and again leaves it for any reason (perhaps this time the survey is completed), then the questions in the End block will present the answers that the respondent has entered previously, and the respondent can then change those answers as required. An End block node cannot be deleted from the survey. If no questions are added to the End block then it will be ignored.

Important
Background variables only have "values" once the respondent has passed them in the survey (and provided the necessary answers). Until this point, the variables are regarded as being empty if they are used in text substitution or scripting. Special care must therefore be taken when creating surveys that include a Start Block if background variables are needed in the Start Block. The background variables MUST then be placed at the beginning of the Start Block such that they are passed first when the interview opens.