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Question type - Equation

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Short description

Note: This question type became available starting in Version 1.92

This question type lets the author create an equation (e.g. a calculation or tailored report) and save it in a database variable.  Equations can use any syntax supported by Expression Manager. If you are handling numeric values make sure that you use the advanced question setting 'Numbers only' as explained below.

Editing an equation

Notice.png
 Hint: Since LimeSurvey 2.06 : you can directly use Equation advanced setting to update the equation. It's used for all language.


If you use the HTML editor and need a clean text or a clean numeric value, you need to use HTML source.

Equation seems OK
View source show extra part, not needed. And if numeric is needed : this can break calculation.
We remove all extra HTML, this ensure to have a clean numeric value.

Alternative is to set your preference to use Popup mode if you use a lot of Equation question type

Core settings

Mandatory

Description

This option allows the survey administrators to request their respondents to answer to certain survey questions. If the mandatory questions are not answered, the respondents will not be able to proceed further. If you have a question with multiple subquestions and you require only certain subquestions to be answered, use the minimum answer attribute located under the Logic tab.


Help.pngIf you use any of the preinstalled themes and the mandatory question attribute is enabled, a red asterisk will be shown next to the question. If you wish to hide it, please check these instructions.


Available options

  • On
  • Off (default)


Relevance equation

Description

If the value of the relevance equation is "1" or "true", the question is "relevant" in the survey context, i.e. it is shown to the survey participant. If not, the question is hidden. Any survey question allows you to specify a relevance equation. This function is the successor of conditions and supports much more complex conditional logic.

Syntax Highlighting

Whenever you save the relevance equation, it is evaluated and syntax-highlighted. Any errors will be color coded so that you can quickly detect and fix them.

Notice.png
 Hint: To check if all the relevance equations are used correctly within your survey, read about our show logic file feature.


Valid values

  • Any equation that makes use of the ExpressionScript syntax, without surrounding curly braces.

Examples

Here are good examples of syntax highlighting.


Advanced settings

Always hide this question (hidden)

Description

If enabled, the question will always be hidden - it will not be displayed to the survey participants. This function can be used in the following scenarios:

  • If you wish to prefill a question with a URL and you want not to have it displayed on the screen. This overrides any conditions used within the survey because the respective question will not even be embedded on the page.
  • If you wish to store or calculate a value on the fly via the ExpressionScript - Presentation.
Help.png Note: A common question type that is used with this function is the Equation one.

Available options

  • On
  • Off (default)


Equation (equation)

Description

The result of the expression you type here will be stored in the response table and NOT the result(s) of the expressions typed in the question textbox. For example, you may want to display several expressions in the question textbox to display the respondents some statistics about herself. However, if you wish to store something different at the same time, then type the desired expression in this field.

This equation is used for all language.

Valid values



Numbers only (numbers_only)

Description

If you enable this option, the participant can only enter numbers in the text box(es).

For the equation question types, this setting indicates that the result could only be a number, not a string. This will guarantee proper calculations/conversions in follow-up equations regarding the decimal mark.

Behavior by question type

  1. Default: If the subject enters a value that is not a number, that value is immediately cleared from the text box so that the subject can enter an appropriate value.
  2. Array (Texts): If the numbers only option is disabled, the "Show totals for" and "Show grand total" options will be overruled, while the total text boxes will not be displayed.
  3. Equation: Enabling this option will force the equation results to be converted to a numeric value. If the equation result is not a number (and not blank), the equation will return NaN, being saved as an empty string in the response table.

Available options

  • On
  • Off (default)


Insert page break in printable view (page_break)

Description

This attribute is only active when you actually print a survey from the Printable View. It forces a page break before the question.

Available options

  • On
  • Off (default)



Show in public statistics (public_statistics)

Description

This attribute allows the survey administrator to chose if a particular question results should be displayed to the survey participants after they submitted the survey.

Help.png Note: To have the statistics displayed on the last page, do not forget to enable this functionality from the presentation & navigation settings. Otherwise, no statistics link will be displayed at the end of your survey.

The default setting for each question is 'Off' (=Do not show the question statistics to the respondents). You have to enable this for every single question if you want to show the survey statistics of that (those) particular question(s) to the survey participants after the survey submission.

Available options

  • On
  • Off (default)



SPSS export scale type (scale_export)

Description

This is used for SPSS export only. This attribute overrides the default scale guessed by SPSS. To learn what the different measurement scales do, please read the related SPSS documentation.

Available options

  • Default (default)
  • Nominal
  • Ordinal
  • Scale