Default

Default values in rtSurvey allow you to pre-populate questions with answers when a respondent first encounters them. This feature can significantly enhance survey efficiency and data quality by providing initial values that are either commonly selected or serve as examples of expected input.

Basic Usage link

To set a default value, use the default column in your XLSForm:

  | type    | name        | label                         | default    |
|---------|-------------|-------------------------------|------------|
| date    | survey_date | Survey date                   | 2024-07-04 |
| decimal | weight      | Respondent's weight? (in kgs) | 51.3       |
  

In this example, the survey date will be pre-filled with July 4, 2024, and the weight field will start with 51.3 kg.

Dynamic Defaults link

rtSurvey supports dynamic default values using functions:

  | type | name | label                              | default  |
|------|------|------------------------------------| ---------|
| date | d    | Enter the date the event occurred? | today()  |
  

Here, the today() function automatically sets the default to the current date.

rtSurvey-Specific Features link

Context-Aware Defaults link

rtSurvey extends the default functionality with context-aware defaults:

  | type    | name     | label           | default            |
|---------|----------|-----------------|---------------------|
| text    | location | Current location| ${current_location} |
  

This uses rtSurvey’s ${current_location} variable to pre-fill the location based on the device’s GPS.

Cascading Defaults link

rtSurvey allows defaults based on previous answers:

  | type    | name     | label           | default         |
|---------|----------|-----------------|-----------------|
| text    | city     | City            |                 |
| text    | district | District        | ${city}-district|
  

Here, the district field is pre-filled based on the city entered.

Default in Repeats link

For questions inside a repeat group, the default is calculated when the repeat is added:

  | type         | name      | label        | default                |
|--------------|-----------|--------------|------------------------|
| begin repeat | visits    | Clinic Visits|                        |
| date         | visit_date| Visit Date   | ${previous_visit_date} |
| end repeat   |           |              |                        |
  

This sets the default visit date to the previous visit’s date.

Best Practices for Using Defaults link

1. Use Sparingly: Only use defaults where they significantly improve efficiency or data quality.
2. Ensure Accuracy: Regularly review and update static default values.
3. Test Thoroughly: Especially when using dynamic or calculated defaults.
4. Consider User Experience: Ensure defaults don’t mislead respondents or introduce bias.
5. Document Clearly: Make sure all team members understand the rationale behind default values.

Advanced Default Techniques link

Randomized Defaults link

rtSurvey supports randomized defaults for certain question types:

  | type              | name    | label        | default           |
|-------------------|---------|--------------|-------------------|
| select_one options| choice  | Select one:  | random(options)   |
  

This randomly selects a default option from the ‘options’ list.

Conditional Defaults link

Use relevance to set conditional defaults:

  | type    | name     | label    | default | relevant        |
|---------|----------|----------|---------|-----------------|
| text    | other    | Specify  | N/A     | ${q1} = 'other' |
  

Here, ‘N/A’ is the default only when ‘other’ is selected in a previous question.

Data Management Considerations link

• Default values are included in data exports, typically with a flag indicating they were default values.
• rtSurvey’s audit trail feature tracks when default values are changed by respondents.

Mobile App Behavior link

• The rtSurvey mobile app supports all default functionalities, including dynamic and context-aware defaults.
• Offline mode may affect some dynamic defaults that rely on real-time data.

Known Limitations link

• Complex calculated defaults may impact form loading time, especially on lower-end devices.
• Some dynamic defaults may not work as expected in preview mode.

Troubleshooting Default Values link

1. Default Not Appearing: Check for syntax errors in the default expression.
2. Unexpected Values: Verify the calculation logic and test with various scenarios.
3. Performance Issues: Optimize complex default calculations or consider alternative approaches.