How to Know if Your eSource is Really Your Source

There is a lot of talk about eSource. And on the surface, it seems simple. If the data is entered directly into an electronic system and not transcribed from a paper form, then it's eSource. But in practice, it's not always so clear. The real question is whether the electronic record is the definitive version of the data. That depends on more than where it was entered. It depends on how the system is structured, how the workflow is managed and how the data is treated throughout the trial.

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In some studies, the electronic form used by a site is designed to be the official record. It has the audit trail. It is locked after completion. It is reviewed by monitors. That is eSource. But in other cases, the same form might just be a convenience layer. The real source might be a paper note in a clinic folder or a PDF saved to a desktop.

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This matters because regulators and sponsors need to know which version of the data is authoritative. If an eCRF entry is corrected, what was it based on? If a monitor reviews a value, are they looking at the original source or a transcription? If two systems show different results, which one stands?

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To know whether your eSource is really the source, start with a few basic questions:

• Was the data first captured in this system, or copied from somewhere else?
• Does this system have a complete, tamper-proof audit trail?
• Is there a clear SOP or protocol note confirming that this is the authoritative record?
• If asked to prove the integrity of this data in an audit, could you do it using this system alone?

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It also helps to map out the full journey of a single data point. For example, a symptom score reported by a participant. Was it entered directly into the ePRO tool? Or was it written in a notebook and transferred by a study nurse? Was it later edited? If so, is the reason documented? Each of these steps affects whether the system that holds the data can legitimately be called the source.

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There are some common traps. For instance, when a participant enters data into a mobile app, but that data is then manually transferred into another system, the app is the source. But if the second system is used to verify or modify the entry, the distinction becomes blurred. If a wearable device collects sleep data, and the investigator later types a summary into the eCRF, the wearable is the source. The eCRF is a transcription.

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In complex studies, source systems often overlap. Wearables, ePROs, site-entered forms, sponsor databases. Declaring which system holds the source is not enough. Each data type needs to be tracked and justified.

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Ultimately, eSource is not a badge you apply to a system. It is a status you earn by proving that the data is original, unaltered and complete in that location. If a digital form is filled out late, corrected without a note or disconnected from the clinical workflow, it might not be the source after all.

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Knowing where your source really is helps you protect it. And when systems are set up with that clarity from the beginning, everything else - compliance, monitoring, analysis - gets easier.

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