Add a consistency check with Custom Alerts

Compatibility:IdSurvey 7IdSurvey 8

From IdSurvey version 8, thanks to Custom Alerts, you can insert consistency checks on any page of the questionnaire.
Custom Alerts consist of a dialog with customized text that prevents the respondent from continuing to the next page if the answers do not meet the desired criteria.
A display condition must be set for each Custom Alert. As with display conditions applied to answers, questions, or pages, if the condition is true, the alert will be displayed.
By enabling the soft option, a button to allow the user to continue to the next page without making corrections will be displayed.

Standard Custom Alert
Custom Alerts

Custom Alert with Soft option
Custom Alerts with Soft option


  • It is possible to insert an unlimited number of Custom Alerts, on any page of the questionnaire.
  • Checks of the conditions set in the Custom Alerts are performed when the Next button of the questionnaire is clicked.
  • This solution replaces the procedure called “control page” that had to be used on previous versions of IdSurvey, greatly simplifying the configuration.
  • The texts of the Custom Alerts support text piping and dynamic text.


In a matrix question, you are asked to break down the importance of certain items into percentages. We set a Custom Alert to check that the total makes exactly 100.

Step 1

Click on the gear button of the page, then on “+” of Add custom alert.

Custom Alerts Step 1

Step 2

Enter the tense “The total is not 100. Please correct before proceeding.”

Custom Alerts Step 2

Step 3

Set the display condition to display the alert if the sum does not equal 100.

if( [Q1.1] + [Q1.2] + [Q1.3] != 100 )
if the sum of the open end answers Q1.1, Q1.2 and Q1.3 is different from 100.
Custom Alerts Step 3


  • Alternatively, you can prefix the negation symbol “!” to override the result of a display condition, e.g. if( !( [Q1.1] + [Q1.2] + [Q1.3] == 100 ) ) which can be read shows the alert if the result of the expression is not true. This solution may be easier to read in some more complex situations.