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Longitudinal Projects

Owned by Mary Irion
Last updated: Sept 19, 2022 by Alyssa Hill
7 min read

Longitudinal projects provide collection of data over time in order to track changes and progress. Longitudinal projects are useful in the following situations:

  • Long Term Studies

  • Clinical Trials

  • Recruitment & Enrollment Combinations

  • Multi-Site Studies

  • Repeating Surveys

It is extremely important to give much consideration to the design, development and testing of your Longitudinal Project. Understanding reporting considerations & needs is critical. Thorough testing is essential for success.

INITIAL CONSIDERATIONS

Enabling longitudinal feature allows any form or survey to be reused over the course of time and provides opportunity to designate specific instruments at specific time points (events). Longitudinal instruments eliminate the need to recreate the same form for multiple time points. Instead, the form is created once and then assigned to various time points throughout the project. Examples of forms used in longitudinal mode include:

  • Medications

  • Lab results

  • Adverse events forms

Basic Setup up of a Longitudinal Project:

NOTE: You must EXPAND the below section(s) to view the full content. Click the (>) carrot to expand.

1. Build an Instrument

2. Enable Longitudinal Functionality

Enable Longitudinal Mode at the project level

  1. Navigate to your project

  2. Select the "Project Setup" tab

  3. Click the "Enable" button next to 'Use Longitudinal data collection with defined events"

     

3. Set up User Rights, Roles, &/or DAG’s

  • Assigning User Rights to team members should be a carefully thought out decision. The consequences of poor user rights decisions could be damaging to the security and integrity of the project. See Knowledge Article User Rights & Roles

  • The User Rights page can be used to determine the roles that a user can assume within a REDCap database. The Data Access Group on the other hand determines the data visibility of a user within a REDCap database. A typical use of Data Access Groups is a multi-site study where users at each site should only be able to view data from their site but not any other sites. Users at each site are assigned to a group, and will only be able to see records created by users within their group. See Knowledge Article Data Access Groups

4. Define Events (and/or) Arms

Define Events / Arms for the Project (e.g., patient visits, tasks or point in time)

  1. On Project Setup Page, navigate to "Define My Events"

  2. Type the title of the event in the text box then click Add New Event

  3. Repeat above steps until each of your events have been created

5. Designate Instruments to Events

Link Instruments to relevant events

  1. From the Project Setup page, navigate to "Designate Instruments for My Events"

     

  2. Select "Begin Editing" button

  3. Click to place a checkbox on the grid for each instrument / form / survey that should be assigned to each specific event

  4. Click "Save"

  5. In order to ensure that other advanced features like reporting and data quality checks in REDCap work properly, always assign the first form to the first event. (i.e. Order your instruments appropriately)

  6. You can link and un-link events in your project during your project set-up and test. Once the project is in Production linking /unlinking events must be done by REDCap Administrator. Reason: You can lose data if you unlink an event.

6. Test, Test & Test

a. It is strongly recommended that you test your projects prior to moving to Production to ensure the project works as desired and reports are presented in the desired format with complete data.

b. Use test data as close to real as possible and simulate the workflow you intend to use.

c. Knowledge Article – Testing Your Project

7. Setup Schedules (Optional feature- not required)

Advanced Setup of a Longitudinal Study

Two Arms and 3 Events are shown here, but you can have as many Arms & Events as you want / need for your study


Expand here for Advance process & details:

Additional Considerations

  1. Best practice to always add Record ID to every arm to prevent REDCap issues, especially if using surveys

    1. Create a "single landing page" with just Record ID. Can be invisible to user with a "Thanks for Participating Page" with Submit to continue.

  2. Actions that can cause data loss in Longitudinal Projects:

    1. Deleting Events

    2. Deleting Arms

    3. Decoupling Forms from Events

  3. If you create additional forms once project is in Production, need to request REDCap support to link forms to Events.

  4. Give much consideration to User Rights. If you want to segregate data based on location but have a form that is common to both sites, a user with rights to that form will see data from both sites.

  5. Branching logic in a Longitudinal Project must identify the Event, Arm and the field name.

    1. Classical Branching Equation:

      1. [field1] = '3'

      2. Longitudinal Branching Equation:

        1. Can cross both forms and events, so need to indicate event and field

        2. [event_3][field1] = '3'

  6. Survey Expiration

    1. Is server time, not what is on your computer

      1. Survey expiration takes all copies of the survey offline.

      2. Warning: If you have survey that is used multiple times in a longitudinal survey if you expire the survey after the first event, be aware that it will expire all the surveys in following events

  7. When defining Events it is important to think about the days offset and use an accurate representation in case you ever want to use scheduling