How to add dynamic fields in REDCap based on another field

Question

I'm building a REDCap survey that requires multiple fields to be added based on the answer from a previous field.

For example, If I enter 4, There should be 4 fields of Role name that appears. The number of Role fields appearing is dependent on answer of the Number of previous roles. Is there a way to achieve this?

Thanks!

Answer 1

The classic way to do this is to create as many fields (role, maybe others) as you might anticipate: [role_1], [role_2], ... [role_N], and each one has branching logic, so that [role_1] displays if [num_prev_roles] >= 1, [role_2] shows if [num_prev_roles] >= 2, [role_N] if [num_prev_roles] >= N.

The other, much more scalable way to do this is to create a repeating instrument 'role details' or something, in which you would configure all the fields you needed to ask for a role, and then allow the participant to repeat it as many times as they want.

The data will be long, rather than wide, i.e. it will come out like this:

record_id	redcap_repeat_instrument	redcap_repeat_instance	num_prev_roles	role
1			3
1	role_details	1		Janitor
1	role_details	2		Dish Pig
1	role_details	3		Sommelier

That is, all the data from the repeating instrument is on new rows, one row per instance. But, it'll work for 1 and it'll work for 10,000.

The challenge with this has been to control the number of instances your participants can create. Traditionally this has been difficult to control, meaning they could enter one, two, or however many they want.

There are at least two good solutions for this.

1. Use a @CALCTEXT field to dynamically generate the survey redirect URL. If the current instance number is less than the value of [num_prev_roles], use the survey URL with [new-instance] appended. Else, use the survey URL of the next survey in the list.

2. Use the @HIDESUBMIT external module to hide the submit button (leaving only the 'add a new instance' button) while [current-instance] < [num_prev_roles], and do the reverse otherwise, hide the 'add another instance' and show only the submit button. This use case is documented on the EM's README.