Electronic Clinical Outcome Assessments, or eCOA, measure how patients feel or function during clinical trials. By capturing clinical data electronically, you can be confident that your patient’s data is high quality and regulatory-compliant. Put simply, eCOA avoids the quality and time issues associated with paper diaries such as illegible answers, transcription errors and inconsistent or conflicting data. ePRO is also recommended by the FDA.

94% compliance with eCOA vs 11% compliance with paper (completed at home/remotely)1
89% median compliance rates using Bring-Your-Own-Device (BYOD)2
88% prefer reporting electronically3

eCOA comes in many forms:

  • ePRO: Patient Reported Outcomes. Patients report on their health via questionnaires or assessments. Examples include quality of life or activity outcomes.
  • eClinRO: Clinician Reported Outcomes. Health outcomes are reported by a clinician. An example may include a physical examination such as PASI.
  • eObsRO: Observer Reported Outcomes. Completed by someone other than the patient or the clinician, such as a caregiver, based on events and behaviors observed.
  • ePerfO: Performance Outcomes are measures from specific tasks the patient is asked to perform. An example might be performing a timed task.

eCOA can be easily integrated with connected devices, wearables or sensors to generate additional evidence in support of your clinical trial.




ERT’s eCOA brings the trial to your patient, enabling sponsors to deliver at-home, remote and fully virtual clinical trials. Our aim is to make participation both convenient and safe while ensuring data remains high-quality and regulatory-compliant. Decentralize your trial with confidence using ERT eCOA – the pioneer and leader in virtual trial solutions.

ERT’s team of experts will advise on best practices for collecting eCOA remotely and how connected devices and training can help maintain data quality-ensuring it is collected at the right time and under the right conditions.


With the move towards decentralization, digital data capture solutions need to be flexible and adaptable to any scenario.

ERT has a long history of working in partnership with its sponsors and CROs to develop the right eCOA solution for their trials – whether this be at home, at site or hybrid.






With experience across all therapeutic areas and 560 indications, ERT’s team of scientific experts are here to advise you on regulatory requirements and best practices when implementing electronic Clinical Outcome Assessments.


ERT is committed to generating the high-quality evidence you need to better evaluate the safety and efficacy of your compounds and ultimately transform patients’ lives. Here’s how:


ERT has been guiding patients in remote data collection since 2005. Our innovative range of virtual, hybrid and remote eCOA solutions enables sponsors to offer patients a convenient and safe way to take part in clinical research while maintaining the high-quality data you need.


ERT’s Science Team reviews every protocol, advises on the most appropriate eCOA solution and is on hand throughout your study to ensure your trial generates high-quality, regulatory-compliant data and evidence.

And our advanced real-time reporting gives sponsors and sites visibility and in-depth insights into how their trial and patients are progressing.


Whether your trial is taking place at site, at home, remotely or a combination of these, ERT will tailor its technology and services to best suit your study. We will ensure that the devices selected are appropriate for your patient population and geographical requirements. Find out more about our BYOD solution!


ERT introduced the 1st eDiary back in 1996 and continues to drive innovation within the industry to advance medical research:

  • ePRO Consortium: founding member including BYOD Working Group
  • Mobilise-D: supporting the development of the 1st clinically-validated mobility endpoint


ERT ships over 90k devices every year to over 110 countries. This global logistics expertise is vital to ensure that trials run smoothly and on time.


ERT’s Science Team will advise on regulatory requirements for your individual study to ensure it meets FDA, EMA or other global regulatory agency requirements.

2.5M Patients

250K Sites

3,800 eCOA Studies

560 Indications


As clinical trials continue to decentralize, sponsors need to be confident that their data remains high-quality. eCOA, integrated with connected devices such as wearables and sensors, is able to ensure that assessments are taken at the right time and under the right conditions. For more information, visit our FAQ below.

In addition, the virtualization of trials means that sites are having to learn new skills, deliver additional services and master new technologies.


Paper COA data is reliable and always works, doesn’t it?

Paper COA is much less reliable than electronic data capture. Paper-based PROs, for example, do not control when data entries are made (e.g., all in one go before a site visit, or forward-filled with made-up answers), or whether patients have completed the entire assessment or not. In fact, recent research showed that 45% of patients in a pain study invented data by forward filling at least once.1 Although paper compliance can seem high, back and forward filling can actually make true compliance very low.

Handwritten entries may also be illegible or the answers might simply not make sense, all contributing to poor quality and unreliable data. By comparison, electronic COA (eCOA) delivers accurate, time-stamped, high-quality, compliant data every time.

When is it critical to use eCOA?

To receive high quality, accurate data, it is critical to use eCOA in the following instances:

  • When patients need to fill in a daily diary or assessment
  • When the data that is captured supports a primary endpoint
  • When monitoring treatment-related suicidal ideation and behavior (SIB)
  • When integrating data with another data source

When is it recommended to use eCOA?

To reduce the data burden and receive consistent high quality data, we recommend using eCOA in the following scenarios:

  • During oncology trials, to support the treatment’s efficacy with additional PRO information
  • In large-scale studies eg across diverse populations and in multiple countries
  • For assessments that require complex calculations or scoring

Paper or eCOA, which one should I choose?

Take a look at the FAQ above about when it’s critical or recommended to use eCOA. It’s also important to remember that eCOA delivers higher quality data and more accurate results than paper data collection, avoiding, for example, transcription errors and inconsistent or conflicting data. Importantly for sponsors, eCOA enables real-time insights into patient safety and study performance. See this infographic for top headlines.

How do I implement or switch to eCOA?

Take a look at our Guide to implementing eCOA in clinical trials. And why not talk to our Science Team who are on hand to answer your questions about how to move forwards with ePRO.

How does eCOA support patients at home?

With the acceleration of decentralized trials, patients are now more responsible than ever for collecting their data, making sure they capture it at the right time and that it’s high quality. eCOA is the ideal solution. Why is that? eCOA makes trials simple to take part in, fitting in with patients’ daily lives and other family or work commitments:

  • ERT’s eCOA decentralizes trials. For patients this means fewer site visits, saving them time and making it much more convenient and simple to take part in a study
  • Patients can also carry on seeing their clinician ‘face-to-face’ with ERT’s Virtual Video Visits
  • It’s easy to collect multiple endpoints. ERT’s eCOA integrates with any connected device such as our at home PEF, blood glucose monitor or heart rate monitor
  • Patients receive automatic reminders to complete their diary entries to help avoid missed diary entries
  • Motivational and educational messaging encourages continued participation in the trial
  • Patients can even take photos at home rather than having to travel to site, within the eCOA assessment, with eCOA Multimedia

How can eCOA increase patient engagement?

eCOA increases patient engagement in five ways:

  • ERT’s virtual eCOA solutions enable patients to complete clinical outcome assessments at home, minimizing the need to travel to site and therefore fitting better into patients’ daily lives
  • eCOA also provides the patient with the choice of using the technology that suits them best – whether this is their own device (BYOD) or a provisioned device, via the web or at a site
  • eCOA captures assessments simply and quickly with automatic branching logic. Assessments are then automatically transferred to the study database. The burden placed on the patient is therefore greatly reduced when compared to using paper diaries
  • When additional endpoints need collecting, ERT’s eCOA easily integrates with other connected devices. Data is automatically transferred to the eCOA device, making the process much simpler than having two unconnected devices or having to manually transcribe readings
  • eCOA sends out automatic diary reminders, motivational messaging and education to patients around their trial participation and condition

When switching to eCOA, will patients' understanding of questions change?

There is mounting evidence in the literature that supports equivalency of PRO measures between paper and electronic modes, and across different devices. This evidence includes two quantitative meta-analyses, which concluded that the mode of PRO administration (paper vs. electronic) does not impact measurement equivalence.7,8 Qualitative syntheses of cognitive debrief and usability studies and expert screen review studies further conclude comparability of PRO assessments when migrating from paper to electronic and across electronic devices as long as eCOA best practices are followed.9,10

Does eCOA meet regulatory requirements?

eCOA meets the recommended regulatory guidelines for collecting and reporting data as required by the protocol while ensuring data quality. This includes ALCOA standards. ALCOA requires data to be Attributable (ie can it be traced back to the patient?), Legible, Contemporaneous (ie is the entry filled out at the right time?), Original (is it the first place the data is recorded?) and Accurate. Because eCOA meets these quality requirements, regulators’ questions about patient-entered data are minimized.

Paper-based collection methods (e.g. paper diaries) may not meet global regulatory standards.

Is eCOA more expensive than paper?

Although at face value it may appear that eCOA is more expensive than paper, there are many hidden, often substantial costs when using paper data collection e.g. labour costs for data transcription and validation – increased variability and more missing data leading to more patients and longer study durations than with eCOA. However, the much bigger issue is the cost to the trial of having inaccurate, poor quality data as a result of paper diaries which may negatively impact the outcome of the trial itself.

eCOA removes hidden costs

Manual data entry, data corrections and incomplete or incomprehensible data in paper-based collection can easily outweigh the cost of using eCOA. With eCOA these challenges, and therefore their associated costs, are minimized. In addition, paper does not enable sites or sponsors to review data in real time. ERT’s eCOA, through its Trial Oversight solution, enables sites and sponsors to identify potential issues early, such as low complying patients and make adjustments or offer additional support to ensure the trial stays on track and therefore on budget.

Reduce provisioning logistics and expenses

By enabling patients to bring-their-own-device (BYOD), study costs can be significantly reduced.

Do patients prefer eCOA or paper?

A number of studies have shown that eCOA is preferred across indications.2-6

Can elderly patients use eCOA?

The assumption is that elderly patients will have a low compliance level to protocol requirements and/or completing unsupervised self assessments, due to e.g. impaired vision, comprehension or dexterity, forgetfulness, lack of computer experience and fear of something that isn’t familiar.

However, results show that patients aged 60+ have the same compliance rate, if not better, than younger participants. ERT eCOA keeps assessments simple, provides reminders and pop-up help, uses larger fonts and target areas and provides appropriate user and confidence training.

  1. “Patient Non-compliance with Paper Diaries,” Stone, A., British Medical Journal, 2002
  2. Khurana et al., State of BYOD: Lessons in Acceptability and Compliance from 30 Trials. Poster presented at Virtual ISPOR 2021.
  3. Ryan et al. 2002. A comparison of an electronic version of the SF-36 General Health Questionnaire to the standard paper version. Qual Life Res;11(1):19-26
  4. Ring A, et al. 2008. A Randomized Study of Electronic Diary versus Paper and Pencil Collection of Patient-Reported Outcomes in Patients with Non-Small Cell Lung Cancer. Patient; 1:105-113. 10.
  5. Tsang LC, et al. 2001. Patient preferences for using technology to track and self-manage diabetes. Journal of Telemedecine and Telecare; 7:47-50 11.
  6. Allena M, et al. 2012. An electronic diary on a palm device for headache monitoring: a preliminary experience J Headache Pain; 13:537-541.
  7. Gwaltney CJ et al. Value Health 2008;11: 322-333.
  8. Muehlhausen W et al. Health Qual Life Outcomes 2015;13:167-187.
  9. Muehlhausen W. et al. Value Health 2018;21:41-48.
  10. Dumais KD et al. ISPOR 2021, accepted abstract.


Our team of experts is available to address questions you may have about our integrated eCOA solutions. Submit your contact information and we’ll be in touch shortly.