How To Design a Case Report Form | 7 Best Practice Steps

Every CRF should be grounded in the study protocol. The protocol outlines the trial’s objectives, including:

• What you’re measuring (endpoints and outcomes)
• Dosage levels
• Visit schedule and frequency

From these details, you can determine exactly what data needs to be collected, and nothing more. The CRF should serve the protocol, avoiding unnecessary or redundant questions that bloat the trial without adding value.

The main purpose of designing your CRFs carefully is to ensure data that is:

• Consistent – Collected with standardized terminology to avoid subjective influences. Imagine you ask two different people to describe the same symptom; you will undoubtably receive two different responses using different wording.
• Complete – All required data points are captured without gaps.
• High quality – Structured to minimize errors and compliance with regulatory standards, e.g. FDA, PMDA

Using controlled terminology aligned with SDTM and ADaM helps standardize responses and avoids downstream mapping headaches.

Free text fields and fields that allow for “Other -please specify” responses should be minimized unless absolutely necessary.

If you ask for too much information in your CRFs, this increases the likelihood that the end user will make an error on the form while filling it out. This can harm the trial’s efficiency and be a drain on resources.

Instead:

• Gather only the data that supports your study objectives.
• Avoid duplication, for example there is no need to collect both a patient’s age and date of birth; your chosen EDC can calculate age based on the DOB.
• Minimize free text and “Other” options that complicate data mapping.

A lean CRF design reduces user fatigue and ensures your dataset remains focused and analyzable.

To avoid confusion and rework during analysis, always use SI (International System of Units).

For example, you can stipulate the units allowed, and this can be multiple units: for height, you might allow both ‘cm’ and ‘in’. Most Findings domains have variables for original units and standard units. Why is that important? Because, if the measurements were made in a US lab, they’d be in ‘in’, but in the UK lab they would be in ‘cm’. Many Electronic Data Capture (EDC) systems have a way to easily convert original units to standard units.

Grouping related questions improves usability and data clarity. With recent updates in ODM standards, you can structure CRFs to keep similar questions together while avoiding overly long forms.

Let’s use the Vital Signs (VS) form as an example. The sponsor wants to collect blood pressure, pulse, and temperature data at each visit. When designing the CRF, these questions should be grouped under a Vital Signs section.

For VS, multiple sets of data points can be collected at a given visit. For example, in the same visit you might want to measure each of the datapoints once the patient has been in a supine position for a period of time, then again after the patient has been standing for a period of time. See the image below from Medidata Rave, which demonstrates how these various measurements would be grouped together.

Formatting a case report form by grouping questions this way makes data entry intuitive and reduces errors during data input. It also lends itself to displaying questions in a log format.

Users filling out CRFs should never be left confused or unsure about what is being asked for. Best practices include:

• Help text in electronic CRFs (e.g., hover-over tooltips explaining field requirements).
• Completion guidelines in PDF format to clarify expectations.

These resources minimize user errors and ensure consistency across the collected data.

Standardization ensures that forms are reusable, compliant, and aligned with CDISC standards (e.g., SDTM). Benefits include:

• Faster study builds, since you’re not starting from scratch with each form.
• Alignment with regulatory expectations (keeping up with new SDTM versions).
• Consistency across studies, for easier data comparison and reuse.

Key takeaway: Ongoing CRF maintenance is just as important as initial design. Approved, standardized forms should be regularly reviewed and updated to reflect new regulatory guidance and protocol changes.

For example, it’s important to review standardized forms before the commencement of a new trial, to assess any changes made to the forms, and decide whether those were study-specific changes, or should be rolled up into the standard.

Below is an example of a poorly designed form. It’s missing:

• Completion guidance
• Controlled terminology
• Measurement units

It also allows free text responses, which can pose problems when mapping downstream.

Below is an example of a well designed form. It works because:

• It provides clear completion guidance
• Questions are grouped logically
• It uses National Cancer Institute (NCI) compliant controlled terminology
• It indicated permitted measurement units

Effective CRF design is a balance of accuracy, efficiency, and standardization. By starting with protocol-driven objectives, minimizing unnecessary data collection, and providing clear guidance for users, you create CRFs that deliver high-quality data while keeping your study lean and compliant.

To learn more about CRF design, download our free best practice guide.