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Understanding eSource, ePRO, and EDC

As the clinical research industry becomes more technology-centric than ever before, it’s becoming more common to work with connected technology platforms to streamline studies. One such example is working with integrated eSource, electronic patient-reported outcome (ePRO), and electronic data capture (EDC) systems. What are their roles in research? Similar in many ways, how do they differ?


Any data initially recorded in electronic format, the Food and Drug Administration (FDA) guidance documents defines eSource as “any combination of text, graphics, data, audio, pictorial or other information represented in a digital form that is created, modified, maintained, archived, retrieved or distributed by a computer system.”

By using eSource, researchers have the ability to produce consistent and legitimate data, as source data will be electronic from the start of the research process. Since data will be electronic, this considerably reduces the risk of submission errors. Additionally, source data are easily made available to sponsors and contract research organizations (CROs) for remote monitoring, as opposed to scanning in paper sources. Because of this, it’s becoming more common for sponsors to require a remote monitoring solution.

An example of eSource is an electronic case report form (eCRF), which holds data collected by a clinical investigator, a medical device, an electronic health record (EHR), automated laboratory reporting systems, or other forms of technology. When research staff use eCRFs, they’re often completed via EDC system.


When participants use ePROs in trials, they have the ability to answer questions and give reports throughout a trial. These are usually done over devices such as a tablet, a smartphone designated for a study, or through an app on a personal device.

There are many benefits to adopting an ePRO technology. Participants typically prefer to electronically report their progress as opposed to keeping a paper diary, as it’s usually quicker and more convenient to report on a device than write things down manually. However, ePROs benefit research staff as well. By centralizing all patient-reported data electronically, it will lead to consistent and more reliable data than paper sources could provide. Using ePRO also reduces duplicate data entry by the staff since data are collected electronically from the start.


As participant data are collected throughout a trial, data are stored in an EDC software, keeping everything in one place. EDCs are used by sponsors to collect the key data needed for clinical trial analysis and reporting. If a site is running an investigator-initiated trial (IIT), it may implement both EDC and eSource together to streamline data collection.

As a way to help with intricate or simplistic studies, an EDC can help sites, sponsors, and CROs achieve success through:

Understanding Their Differences in Research

While each of these elements work to enhance research operations, there are differences among each of them. Owned by the site, eSource is designed to collect every piece of information researchers may need from a standard of care, research, and operational workflow perspective. An example of this is lab data. In eSource, researchers typically collect details such as a participant’s initials, their date of birth, the date and time of the sample collected, lab results, etc. Through eSource, researchers have a very detailed outline of how a study is going.

On the other hand, EDC is typically owned by the sponsor of a research study or a site if they are conducting an investigator-initiated trial (IIT). Additionally, EDC is a subset of eSource because it doesn’t collect protected health information (PHI). When collecting lab data, an EDC only needs the date and time of collection and the test results; not as thorough as researchers collecting eSource.

Used as a way to eliminate duplicate data entry, ePRO is considered to be another type of eSource. While eSource itself is collected by researchers, ePRO is generated by the participant directly. An example of this is a participant completing a survey to provide feedback about the study.

Even though there are differences between eSource, EDC, and ePRO, each element works to enhance operations and provide a more thorough understanding of how the study is going as a whole, from data collected to participant experience.

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