"REDCap (Research Electronic Data Capture) is a secure, web-based application designed exclusively to support data capture for research studies. REDCap provides: 1) an intuitive interface for data entry (with data validation); 2) audit trails for tracking data manipulation and export procedures; 3) automated export procedures for seamless data downloads to common statistical packages (SPSS, SAS, Stata, R); 4) procedures for importing data from external sources; and 5) advanced features, such as branching logic and calculated fields." (REDCap Website 2010)
Data Entry Forms
Figure 1 (REDCap Survey Demonstration 2010)
Figure 2 (REDCap Survey Demonstration 2010)
Data entry forms are created using a visual click and drag design tool. Figure 1 shows development of a form. Fields can be edited to define the data type to store and other properties. Figure 2 shows editing a field with two useful options: one for validation and the other marking the field as containing identifiable data. Designing the form also creates the database backend to store the entered values.
Data Entry Form Features
Following is a short list of some of the features available:
- Data entry forms can be saved as a PDF file and printed for completion by hand
- Forms can be marked as incomplete, awaiting verification and completed
- Records can be locked to restrict further modification of data
- Questions can branch to further questions (e.g., answering female to gender could reveal a question about pregnancy)
- Files can be attached to each record that is entered
REDCap permits management of multiple databases and each database is assigned to one study for data collection.
The database can be set to one of three status levels:
- Development status
- Production status
- Inactive status
This is the status during the design phase. Test data can be entered using the forms or using data import. The test data will automatically be removed when the status changes to production.
Production status indicates that the database is ready for collected data to be entered and stored in the database.
Once data collection is complete the status is changed to inactive. The data can still be accessed and, but most database functionality is disabled. If further data collection is required the status can be changed back to production.
The database can be archived when no longer needed. Although archiving removes it from the list of active databases it can still be accessed and, if further data collection is required, re-activated.
Figure 3 (REDCap Survey Demonstration 2010)
REDCap requires each user to login before accessing any data and once a user is logged in they are subject to assigned rights as shown in Figure 3. The data is stored on a MySQL database that also has its own security policy. REDCap also supports LDAP which fits in well with epiLab.
Audit Trail and Logging
All actions on related to a database are logged from actions such as renaming a field or downloading a PDF to modifying the database itself or altering user rights. Events to be viewed can be filtered by type, user, record and chronological order. The complete log file can be downloaded as a CSV.
REDCap provides a file repository for each database. The files can be uploaded by users with appropriate rights and downloaded by other users of the database. Any previous data exports are also stored here and can be downloaded again in a choice of formats: SPSS, Excel SAS, R and STATA.
Data Export and Import
The data export tool allows the user to download data for specified forms and, for finer control, specific fields. The download formats available are: SPSS, Excel SAS, R and STATA.
Figure 4 (REDCap Survey Demonstration 2010)
Figure 4 shows de-identification options available during data export.
The Calendar application can be used as a project calendar within the databases to help organize schedules and keep track of any upcoming events. It can be viewed in a daily, weekly, or monthly format.
Graphical View and Stats
This tool allows users to view real-time plots and statistics about the data collected in their database, which includes scatter plots, bar charts, and descriptive stats. Other functionality exists, such as finding missing values and highest/lowest values for a database field, which can aid in cleaning data.
REDCap Website 2010. Software. Available at: http://www.project-redcap.org/software.php (Accessed 16th August 2010).
REDCap Survey Demonstration 2010. Available at: https://octri.ohsu.edu/redcap/ (Accessed 5th August 2010).