Quick guide
- Create calculated variables
- Calculated variables as feedback
- Calculated variable for time rule intervention
Calculated variables are made up of the participant’s answer on an specific item within a module.
Create Calculated Variables
Step 1. Choose the item

- On the left menu, click on the tab named “Modules”
- Open your module
- On the right side, click on “Content items”
- Choose an item
Note: Calculated variables will only work with numerical item types (Number input, number slider, number dropdown, and number choice).
Step 2. Enable numeric calculation

Once you have chosen your item, a preview screen will open.
1. After filling in the details of your item, tick the box next to “Used for numeric calculation”
2. Give your numeric calculation a name
Note: no whitespace is allowed
3. Click on the “Save” button
Step 3. Add calculated variable

- On the left menu, click on the tab named “Calculated Variables”.
- Click on the “Add calculated variable” button
- Enter a unique calculated variable name in ID and a description
Note 1: Names of calculated variables must have at least a letter and can have an underscore, and numbers.
Note 2: Calculated variables are unique so they cannot be repeated in the same study. - Input your equation
Note: Under functions, use the list of formulas to create calculated variables easier - Click on the “Save” button
Functions explained

Functions:
- “+” gives the addition of variables
- “-” gives the subtraction of variables
- “*” gives the multiplication of variables
- “/” gives the division of variables
- “^” gives the exponential value of a number
- “SUM_ANS(N)” gives the sum of the different participant responses of the variable.
- “NUM_PS(N)” gives the total number of participants for an indicated variable. Example: three participants are assigned to an intervention, this function will return 3.
- “NUM_P_ANS(N)” provides the number of participants who answered the indicated variable. Example: three participants are assigned to an intervention, two gave an answer. This function will return 2.
- “MODE_ANS(N)” gives the most responded number of the indicated variable.
Note: If there is no mode this function will return the average. - “COUNT_ANS(VAR,VAL)” provides the number of times the value of the responses were given in the indicated variable.
Calculated variables as feedback
Step 1. Enable dynamic text

- On the left menu, click on the tab named “Modules”
- Use a different module by creating a new or using an existing module
- On the right side, click on “Content items”
- Create a new item or choose an existing item
Note: any item type would work - In the question field, click on “Dynamic text”
Step 2. Select calculated variable

- On the pop-up screen, click on “Select calculated variable”
- In the dropdown list, select your calculated variable
- Click “Ok”
Note: A code will now appear on the preview screen. This code will show a number once the items used for the calculated variable are filled in by the participant.
Calculated variables for time rule intervention

- After you have created your calculated variables, click on the tab named “Interventions” on the left menu
- Open an intervention
- On the right side of the screen, click on “Modules”
- Click on the alarm clock symbol next to the module you want to time
- Click on the “Enable Timing Rules” button
- Choose “Based on a calculated variable”
- Select the equal or not equal qualifier
- Select the value
Note 1: If you want to add multiple timing rules together, click on “Add Rule” each time you add one rule
Note 2: If you want to add multiple timing rules separately, click on “Add Timing Rule” each time you add one rule - Once you have finished adding the timing rules, click on the “Save” button
For more information on time rule interventions, see https://bmslab.utwente.nl/time-rule-interventions/