Redcap is when data capture leads to good: An overview and tips for best practice
Authors: Shane Fernandez BPsych (Hons)1, 2, Dr Amy Page PhD3
1. Collaborative Genomics and Translation Group, Centre for Precision Health, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia
2. Australian Alzheimer’s Research Foundation, Nedlands, Australia
3. Centre for Medicine Use and Safety, Monash University, The Alfred, 55 Commercial Road, Melbourne, Australia
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If you have been involved in collecting or managing data for research studies, chances are you have heard the word ‘REDCap’ being thrown around. Here we will run through some basics about what REDCap is, why it is so often considered the preferred tool for your data needs, and provide some key pointers to help you get the most out of your project.
REDCap (Research Electronic Data Capture) is a web-based solution for collecting and managing research data. It was designed by researchers, for researchers, which translates to an intuitive and user-friendly system that ticks a lot of the boxes that are likely to be important to you when designing your project. Let’s start by discussing some of key features that make REDCap a valuable platform to help you manage your research data. These are:
- Security and regulatory compliance: Protecting participant data is obviously a priority. However, if you do not have an IT background developing a solution that protects your data and allows you to meet your regulatory responsibilities may seem like a daunting task. Providing a secure platform for your data is one of the key strengths of REDCap. Most institutions have minimum requirements for the handling of research data and REDCap is often listed as a preferred platform. This is because there are a few assurances that are standard in REDCap. Importantly, all data are transmitted over a secure connection by authenticated users and all activities and changes to data are logged. REDCap projects can also be configured to comply with standards such as the US Food and Drug Administration’s Title 21 CFR Part 11 and the Health Insurance Portability and Accountability Act Security Rule that can apply to sensitive data.
- Free to institutions belonging to the REDCap Consortium: REDCap is completely free to use for research teams at partner institutions. You can check whether your organisation is a member on this webpage.1 If not, your institution can join for free but there are a couple of requirements that bear mentioning. Firstly, only non-profit organisations are eligible to join the REDCap Consortium but a fee-based cloud service2 is available to for-profit organisations. Second, membership is also dependent on sufficient internal IT infrastructure and support being available at your institution. As the REDCap license agreement prohibits the outsourcing of IT support, this means that your institution must have its own IT department who are willing to support the projects. Note that support in this instance means facilitating the REDCap instance at your institution; you or your team will generally be responsible for building the projects and instruments (or outsourcing this).
If you are planning to apply to join the REDCap Consortium, the technical requirements3 section of the REDCap webpage will come in handy when discussing with your institution’s IT department. Staff supporting the REDCap instance can join the REDCap community site4 and gain access to technical documentation, forums, and other resources to assist in their roles.
Unfortunately, REDCap is not currently available for individual or personal use but if you will be running your project through a university, you shouldn’t have a problem joining the REDCap Consortium (most Australian universities are already members).
- Basic functionality can be extended using external modules: Many external modules are available5 to technical staff. Software developers contribute these to add specific functionality to REDCap based on the needs of projects around the world. Your administrator (within the IT support staff) can help you to identify and implement external modules that may be appropriate for your project.
- Flexibility in designing instruments: REDCap instruments can be directly distributed to participants as surveys or set up as ‘electronic Case Report Forms (eCRF)’ for data entry by study staff. These can be linked using a unique participant ID number which means that surveys can be linked to data subsequently collected on site and vice versa. There is no need for double handling survey data as this will automatically be entered into the system. You can also easily share survey links in your recruitment material and, for repeating surveys, reminders and links can automatically be sent to participants who have provided their email addresses.
- Simple design of projects and instruments: There is no coding required for designing your project or your instruments (i.e. surveys and eCRFs). Projects are easily defined using REDCap’s web interface. For instruments, you have two options: the online designer and an offline data dictionary. These both contain the same information, and it is easy to switch between them.
- Online designer: The online designer is managed entirely on the REDCap web application. You can ‘point and click’ to edit your variables and there are annotations to help you along the way. This is a straightforward way to create instruments but can become tedious for larger instruments.
- Data dictionary: The data dictionary is a specially formatted spreadsheet which includes all the information about your forms. It can take a little more to get used to than the online designer but once you get the hang of it, it can be easier to work with. This is especially true for larger instruments because you can copy and paste sections that are shared, and you do not have to constantly click to move back and forth when editing variables. Once you have finished making changes, save the file and upload it to REDCap. If you receive an error message, it likely means that you have not adhered to the formatting requirements. These must be strictly followed because they define the format which makes the file readable by REDCap.
- Every change made in the online designer results in an updated data dictionary being automatically created in REDCap. You can download these for editing at any time. When you are first starting out, it may help to design your first instrument in the online designer, and then download the data dictionary. This will help you to make the connection between what is included in the data dictionary and what is built in the instrument.
- Instrument Library: REDCap users around the world upload instruments to a shared library.6 These instruments can then be downloaded and implemented easily by other users. If you have commonly used forms, you may find that someone else has already done the hard work for you! Even if it’s not quite right, it might be quicker to edit a template than build a form from scratch.
- Scheduling feature: It is possible to do all of your scheduling in REDCap. Once you have defined the expected interval between study events and an allowable window, REDCap can generate an editable schedule with suggested dates already entered when the first event date is provided. Appointment times and dates can be changed at any point and are automatically added to a useful study calendar.
When designing your REDCap project, it is important to be mindful of all the purposes collected data will serve in your research. As clinicians, we perhaps first think of the user experience — whether it is straightforward for our patients to use, how we will enter data, what information we would like to have available at visits, and so on. While these are no doubt important, we also need to remember how the collected data will be used. Datasets will ultimately be extracted from REDCap, likely imported into a statistical package such as R, and analysed to answer research questions. This raises further considerations, but because these processes are down the line, they can sometimes be overlooked at the design stage. This can unfortunately result in a need for messy retrospective corrective measures if issues with the collected data are identified midway through the project. The time and effort needed for data cleaning at the end of the project can also be reduced by taking care at the initial design stage.
Below are some basic tips for designing your project with consideration given to both REDCap users and to users of the data it manages. However, REDCap is a powerful platform with functionality that can be extended by a wide range of external modules, as previously mentioned. It is impossible to cover everything here, but we believe that following these tips will get you well on your way along a successful REDCap journey.
Tips for User-Friendly REDCap Surveys and Forms
- For eCRFs, it is good practice to design forms to mimic their paper copies as closely as possible. This makes data entry more intuitive and can reduce the risk of data entry errors. Aim to follow the order of presentation, layout, and data format in the paper copy of the forms. Things like presenting multiple choice options as horizontal rather than vertical (use the custom alignment option for this) or entering data into a table rather than a list (use the field embedding feature for this) can help your electronic forms more closely match their paper sources.
- Users should rarely have to enter the same data twice. You can ‘pipe’ in previous responses from an earlier event in the same project using the @DEFAULT action tag. This tells REDCap to enter a default value which is the same as some earlier collected/entered variable. This feature can be used if there is a need for the same data to appear on multiple forms. It can also be used for things like medicine lists across visits where it is possible that responses haven’t changed. However, if you are using the feature in this way, make sure to be clear that the previous responses have been automatically filled and the user should check their accuracy and update as necessary.
- Branching logic can make the appearance of your forms less cluttered and make it easy to find things. This allows you to show or hide items depending on whether defined logical criteria are met. Fields that don’t apply can be skipped all together.
- Defining important fields as required is a useful way to minimise missing data due to data entry errors. However, if missing collection is reasonably common for a particular variable, this can be a nuisance for users. In such circumstances, it can be helpful to have a required field asking if the data was collected, and subsequent details to show only if the answer is ‘yes’ (using branching logic). This has the additional benefit of making it possible to conclude whether data are genuinely missing or whether its entry was omitted in error.
Considerations for your REDCap Data
- Field validation is useful in making sure that data are being entered in the expected range and format. For example, for systolic blood pressure, you can tell REDCap that you want whole numbers only (i.e. integers), and you expect values between 70 and 200. Values outside of the defined range (but not format) will be accepted but will trigger an alert asking the user to confirm their accuracy. This can prevent simple typos at the time of entry.
- Remember, in both REDCap logical statements and statistical software, variable names will have to be typed out to be called and you (or your statistician) will not want to repeatedly refer to the codebook to know which variable you want. As such, names should be short and intuitive. Spaces are not allowed, and uppercase letters are changed to lowercase. This generally makes it compatible with use in statistical software, but it is still important to choose names that are sensible and make it is easy to infer what is being captured.
- If multiple sites are being used to collect the same data, using the same REDCap instruments (particularly variable names) will mean your data are harmonised and ready to be pooled. Sharing REDCap data dictionaries at the design stage is a simple way to ensure this.
- It is a good idea to work with your statisticians/data analysis team when designing forms to ensure that the key variables are in the expected format for the planned analyses.
The REDCap website7 has a wide range of videos introducing you to the application and the specifics of how to use it. You can also sign up for a free one-week trial account which allows you to learn your way around REDCap and to practice creating instruments — even if your institution is not a member of the REDCap Consortium. This is probably the best way to become quickly acquainted with the system. You will also find a huge range of resources on YouTube and Google, but it is best to start with the REDCap website before jumping into these.