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Record Labels, Auto-Numbering & Unique Identifiers

 

This article reviews the below topics related to Record keeping

  • Unique Identifier: The first variable listed in your project is the unique identifier which links all data for a specific record across all instruments

  • Auto-Numbering: REDCap is set to automatically number records by default

  • Custom Record Label: Used to display a specified field next to the participants record number

  • Secondary Unique field: Unlike the value of the primary unique identifier field, it will not be potentially visible in a URL, but does allow for a secondary field to be displayed next to the record number

To see these in action, expand the topic below that you wish to review


Unique Identifier

The unique identifier must be a 'text' field. Unique identifier values will be visible at the end of the URL – and likely cached in web browsers – as individual records are viewed or entered.
(Example URL: https://xxx.xxx.xxx/redcap/redcap_vx.x.x/data_entry.php?pid=xxx&p age=xxx&id=ID_VARIABLE_VALUE.)

  • The first variable listed in your project is the unique identifier which links all data for a specific record across all instruments. This field is the record ID field, which is the first field in the project.

  • For all newly created projects, it is automatically defined as the Record ID field, which will be the first field created by default in ‘Form 1’

  • The Record ID value is numeric and auto-increments starting with the highest value in the project. If no records exist, it will begin with '1'.

  • This field is special because it is used to store the names of the records in your project. Thus the record ID field cannot be deleted or moved but only edited. If you wish, you may change the Unique Identifier field label or even its variable name.

 

The below example show cases a Data Entry form as the first instrument in a project, where the unique identifier has been updated from ‘record_id’ to ‘study_id’

If you wish the edit this field, note the below:

  • Edits to this field must be made prior to real data collection

  • Do not use Protected Health Information (PHI) identifiers such as medical record number or date of birth or initials as the unique identifier, as it could be accidentally displayed if a URL is created. This is an additional precaution to preserve research participant confidentiality from displaying in the URL and becoming cached. 


Auto-Numbering of Records & how to disable

When your first data collection instrument is enabled as a survey, auto-numbering is mandatory for the project.

If you plan to manually enter your unique identifier and wish disable auto-numbering, follow the below instructions.


To disable auto-numbering, follow the below steps:

NOTE: This can only be disabled when your project is in Development mode.

  1. Navigate to "Project Setup"

  2. Within “Enable optional modules and customizations” box, you’ll see “Auto-numbering for records” in green font.  Click “Disable” and your project will no longer auto-number.

  3. You will now be able to enter your own unique identifier when a new record is created (this is a manual process)


Custom Record Label

Custom Record Label may be used to display a specified field next to the record number. For example you may choose to display a participants name to ensure you are selecting the right record.

You may append other data and/or static text to any record name (e.g., Study ID) as the record is displayed on your data collection instruments, such as inside the drop-down lists when choosing a record and at the top of the page after being selected. Simply provide the text you wish to display below, and place any variable names inside square brackets [ ], after which the data collected for those variables for that record will replace the variable in the text.


To create a custom record label, follow the below steps:

  1. Navigate the ‘Project Setup’ > 'Enable optional modules and customizations' section

  2. Click ‘Additional Customizations’

  3. Select the first box to enabled Custom Record Label functionality, you’ll notice the previously greyed out box is now available for you to use

  4. Input your variable names inside square brackets and/or add static text

    1. If using a longitudinal project with events, you’ll need to prepend the event name to the front of each field variable.

    2. ex) [event1_arm_1][first_name], [event1_arm_1][last_name]

  5. Click ‘Save’

  6. Navigate to your Records status dashboard to check you’ve configured your Custom Record Label to display correctly


Secondary Unique field

The data values entered into the (optional) secondary unique field must be unique. Unlike the value of the primary unique identifier field, this will not be visible in a URL.

You may designate a text field to serve as a unique constraint whose value cannot be duplicated or shared by any other record in the project. When a value is entered or imported for the secondary unique field, it will be checked in real time to ensure it is not shared by another record, and if so, will ask the user to enter another value.

This means that if a participant is completing a survey for a second time in which this feature is enabled, they will see the following pop-up box:

This feature should be enabled in Development mode before real data collection begins

If you are already collecting real data and there are duplicates in your project, you cannot enable this feature as it's not possible to specify the combination of two or more fields be unique.


To enable a Secondary Unique field, follow the below steps:

  1. Navigate the ‘Project Setup’ > 'Enable optional modules and customizations' section

  2. Click ‘Additional Customizations’

  3. Select the checkbox next to ‘Designate a Secondary Unique Field’

    1. If you want the field value to be displayed next to record number, be sure to select the display preference as shown above.

    2. If you select both display options, the field label & field value will be displayed as showcased below

    3. If neither display options are selected, the secondary unique field data will not be displayed (only record number will be shown), however the unique field check will continue to be preformed by REDCap.


Frequently Asked Questions

Q: If the unique identifier is arbitrary to me, can the system auto-assign a unique value to each of my records?

Yes. You can enable auto-numbering for naming new project records on the Project Setup > Enable optional modules and customizations page. This option will remove the ability for users to name new records manually and will instead provide a link that will auto-generate a new unique record value. The value is numeric and increments from the highest numeric record value in the project. If no records exist, it will begin with '1'.

Q: How can I set the default auto-numbering to start at a particular number such as 2000?

You can disable auto-numbering and add the first record using the ID number as the start value. Once this record is saved, you can enable the auto-numbering customization, so subsequent records will be created starting after 2000.

Q: What's the difference between the unique identifier, secondary unique identifier and the redcap_survey_identifier?

  • The first variable listed in your project is the unique identifier which links all data for a record.

  • The secondary unique field allows you to identify another unique identifying value of the field (e.g, name, subject number).

  • The redcap_survey_identifier is the identifier defined for surveys when utilizing the Participant Email Contact List and sending survey invitations from the system. The "Participant Identifier" is an optional field you can use to identify individual survey responses so that the participant doesn't have to enter any identifying information into the actual survey. This field is exported in the data set; the email address of the participant is not. More info: Participant Identifier