Why use validation?
Validation is a powerful way of ensuring data collected for number questions in surveys is good quality, you can set limits to the numbers entered to ensure it makes sense, and you aren't receiving responses which give impossible answers and no way of obtaining correct data. By preventing inaccurate data being collected at the point of data entry, it makes data checking and validation much easier and quicker.
Simple validation
The simple validation option can be inserted into a question by clicking 'Add Validation' in the Question building window (Image 1).
This allows you to specify a range of numbers you would accept in response to the question, for example, if you are asking about the pH of water you would want to limit it to responses between 0 and 9 to ensure that responses recorded are accurate.
It's important to specify an error message to ensure that enumerators know the limits of the numbers they are able to enter.
Advanced validation
In some cases, rather than specifying a number, you want to validate answers provided based on answers given to other questions in the survey. A good example of this is to check the total number of household members against the number of men and women living in the household.
- To add an Advanced Validation, click "+ Add Advanced Validation". (Image 5)
- Build the condition that must be met in order for the answer to meet the validation criteria. In this case, select the question 'how many people in this household' then press the 'Select' button. Click on the Survey Fields table at the top of the pop-up window and find the 'How many men...' field, click on this to add it to the condition. (Image 6 and 7)
- Click the + icon below the field you just inserted, then press Select to add the 'how many women...' field.
