Repeating Data Collection in REDCap

Illinois REDCap | IHSI Version Date July 14, 2022

The repeating instruments and events module is a REDCap feature useful for collecting data multiple

times using the same instruments without set time points. There is also no limit to how many times a

repeatable instrument or event is repeated for an individual record. This is useful for instances in which

data will be collected using the same instrument multiple times, but the number of times will vary

across participants. Repeatable instruments can be used in classic and longitudinal projects, while

repeatable events are only for longitudinal projects.

Example Use Cases for Repeatable Instruments/Events

• Participants are asked to complete a form each time they are admitted to a facility, like a

hospital;

• Forms for tracking samples;

• Contact logs, adverse event forms, or billing logs; or

• A parent is asked to complete a survey for each child they have.

How to Set Up Repeating Instruments and/or Events

1. On the “Project Setup” tab, select “Enable” next to “Repeatable instruments” in the “Enable

optional modules and customizations” box.

2. A pop up will appear with a list of your instruments. Select which instruments you would like to

be repeatable.

Illinois REDCap | IHSI Version Date July 14, 2022

a. Custom label for repeating instruments – Variables can be piped here to customize what

appears next to each repeated instance on an individual’s record dashboard.

b. If you have the longitudinal module enabled, this pop up will be organized by event

name and you can select whether to repeat instruments within the same event together

or independently of one another.

How to Add a New Instance as a Form

1. While logged into REDCap, go to “Add/Edit Records” and select the record needed.

2. Click “+” or “+ Add New” on any repeating instrument or event to add a new instance. You can

also add a new instance from within the instrument.

a. In the example below, the blue status circle next to the form means a mix of complete

and incomplete instances.

Illinois REDCap | IHSI Version Date July 14, 2022

How to Add a New Instance as a Survey

There are three different options for entering a new instance as a survey. Each option has its own pros

and cons that should be weighed carefully based on your project needs. Additionally, the options listed

are not mutually exclusive and can be used in combination together for multiple surveys within a

project.

“Repeat the Survey” Button at the End of a Survey

When a survey is enabled as a repeating instrument, the survey option “Allow respondents to repeat the

survey” appears under “Survey Termination Options” in “Survey Settings.” Selecting this will create a

customizable repeat button for participants. The repeating button can appear next to the submit button

before the survey is repeated or after the survey is completed on the survey completion page. If

enabled, a green repeat arrow appears next to the instrument on “Online Designer.”

Note: The “Repeat the Survey” button option is not available for repeating events with instruments that

repeat together (i.e., not independently of one another).

Sending Automatic Survey Invitations (ASI) for Repeating Instruments

Automatic survey invitations, or ASIs, can be set up to send survey links for a repeating instrument at a

recurring interval and can be used for repeating instruments and instruments on repeating events. This

method will also work with Twilio SMS and Voice Calls.

Illinois REDCap | IHSI Version Date July 14, 2022

How to Set Up an ASI for a Repeating Instrument

1. From the “Online Designer” page, select “Automated Invitations” next to the repeatable survey

for which you would like to send invitations. A “Define Conditions for Automated Survey

Invitations (ASI)” pop up will appear. Complete steps 1 through 3.

2. ASIs for repeatable surveys have an additional step compared to traditional ASIs. This is where

you will set how many times and how often the survey invitation should be sent. Each invitation

will be a new instance and all scheduled invitations are based on when the first invitation is

sent.

a. Note: Scheduled ASIs for repeatable surveys can be cancelled via the “Survey Invitation

Log.” However, cancelling one invitation will delete all scheduled future invitations for

that participant’s survey.

3. Don’t forget to set the ASI to “Active” and click “Save!”

Sending Alerts for Repeating Instruments

Alerts can also be used to email participants a link to create a new instance of the repeating survey. This

is done using the “Smart Variables” [survey-link] or [survey-url] and [new-instance] in the alert message.

Compared to ASIs, the alert module provides more flexibility in how the alert is triggered, scheduled,

and where it is sent.

Below is an example of how [survey-link] or [survey-url] and [new-instance] can be used in an alert

message. In this example, the following syntax is used to create the survey links to a new instance of the

instrument named “Exercise Questionnaire”:

[survey-link:exercise_questionnaire:Exercise Questionnaire][new-instance] and [survey-

url:exercise_questionnaire][new-instance]

Illinois REDCap | IHSI Version Date July 14, 2022

Importing Repeating Instances

When importing data into a repeating instance, it is important to notate the instance, instrument, and if

applicable, event. See the Importing Data to REDCap document for more detailed information.

Exporting Repeating Instances

Data from repeating instruments and events will export in a long format. You may need to reformat

your data after it is exported. In the example below, records 1 and 2 have data for the repeating

instrument “Practice Form” which contains the question “Does the pet have a vet?” while record 3 does

not.

Using Fields from Repeating Instances in Piping and Logic

Piping and logic that reference fields in repeating instruments will always take data from the first

instance of that instrument unless a “Smart Variable” is added after the variable name to specify which

Illinois REDCap | IHSI Version Date July 14, 2022

repeating instance REDCap should refer to. Additionally, if you have the longitudinal module enabled

and the field you are referring to is in a different event, you must include the unique event name (e.g.,

[event_1_arm_1]) before the repeating instance variable. You cannot refer to data from a specific

instance number.

For example, the equation below uses smart variables to calculate a cumulative working time,

[supp_total], from all previous instances by adding up [supp_time] in every instance. The smart variables

[current-instance], [first-instance], and [previous-instance] indicate to REDCap which [supp_time]

number to use in each part of the equation:

if([current-instance]=[first-instance], [supp_time][current-instance], sum([supp_total][previous-

instance], [supp_time][current-instance]))

A list of smart variables that can be used with repeating instances and events can be viewed by clicking

the green “Smart Variable” icon on the “Project Setup” page, “Online Designer” page when building an

instrument, “Add or Edit Alert” pop up, and other areas of the REDCap interface.

Repeating Instances and the Survey Queue

Survey queues that contain repeating instruments work best when the “Repeat the Survey” button is

enabled, the queue is not hidden for participants, and participants have access to their survey queue

link.