We support research that will provide reliable, useful information to help people make informed healthcare decisions and improve healthcare delivery and outcomes. Patients, caregivers, clinicians, and other healthcare stakeholders guide the research we fund.


A female African-American physician consults at the bedside of a male African-American patient who's lying down.

This work, described as patient-centered outcomes research, or PCOR, is a type of comparative clinical effectiveness research, or CER. Our funded work includes both randomized controlled trials and well-designed observational studies. We also fund research that addresses how to improve the methods for conducting PCOR.

Patient-Centered Outcomes Research (PCOR)

A relatively new research field, PCOR focuses on outcomes most important to patients. PCOR findings can help patients and other healthcare stakeholders, such as caregivers, clinicians, insurers, and policy makers, make better-informed decisions about their health and healthcare options. This type of research answers questions including:

  • Given my personal characteristics, conditions, and preferences, what should I expect to happen to me?
  • What are my options? What are the potential benefits and harms of those options?
  • What can I do to improve the outcomes that are most important to me?
  • How can clinicians and the healthcare systems they work in help me make the best decisions about my health and health care?

To answer these questions, PCOR does the following:

  • Assesses the benefits and harms of specific approaches for managing clinical conditions
  • Includes individuals’ preferences, autonomy, and needs, focusing on outcomes that people care about, such as survival, function, symptoms, and quality of life
  • Includes a variety of settings and diverse participants

By including patient and other stakeholder perspectives throughout the research process, PCOR aims to produce results that can be put into practice after the research is complete. (Learn about how we established the definition of PCOR.)

Comparative Clinical Effectiveness Research (CER)

CER compares the effectiveness of two or more interventions or approaches to health care, examining their risks and benefits. CER findings assist clinicians, patients, and other stakeholders in making informed decisions that improve health care. Comparing two or more interventions distinguishes CER from other types of clinical research. It can both validate a particular intervention and identify which treatments best meet a certain population’s needs.

We are interested in CER that examines any of the following:

  • Strategies for prevention, screening, diagnosis, treatment, or management of clinical conditions
  • Methods to improve delivery of care
  • Interventions to reduce or eliminate disparities in health and health care
  • Health communication techniques

At PCORI, we fund research on approaches that are effective but have not received adequate comparison with other approaches in previous studies. We particularly encourage research projects that take place in typical populations and address outcomes important to patients.

PCORI is authorized to consider the full range of clinical and patient-centered outcomes relevant to patients, caregivers and stakeholders. Additionally, our awardees are encouraged to collect data, when appropriate, on the potential burdens and economic impacts of the utilization of medical treatments, items, and services.

Types of PCOR and CER

PCORI supports the work of researchers conducting several categories of PCOR and CER studies.

Randomized Controlled Trials (RCTs)

In comparing interventions, it can be difficult to separate the effects of interventions from the effects of other factors that vary between patients. RCTs, often considered the most powerful clinical research tool, provide a way to deal with this challenge.

In RCTs, researchers randomly assign participants to interventions and then measure the health outcomes. This random assignment makes the distribution of factors that might affect outcomes likely to be similar across groups. So, researchers can attribute differences in outcomes to the intervention. However, RCTs may not be practical for assessing rare outcomes or long-term effects. Also, low participant compliance with an intervention or high drop-out rates can hinder trials.

Observational Studies

Observational studies can complement RCTs in answering patient-centered questions. In these studies, interventions are not assigned randomly but as a part of normal clinical care. Observational studies may be useful when ethical or practical reasons prevent researchers from assigning participants to particular study groups, or when an effect is rare or slow to appear. Electronic health databases can make conducting observational studies possible in large populations in clinical settings. Other observational studies use previously collected data, such as from a registry.

The challenge of observational studies is that the variability and complexity of patients, and of their circumstances and the care they receive, often make it difficult to conclude whether specific clinical approaches are responsible for the observed outcomes. However, statistical techniques can sometimes correct this problem and increase confidence that the observed findings are believable.

Pragmatic Clinical Studies*

Pragmatic clinical studies aim to include a broad range of patients in the research, so that healthcare providers can have confidence that the results apply to their own patients. These studies occur in routine clinical settings. They are often large, in part to provide enough data to understand how the results may vary in patient subgroups. These studies often use routinely collected patient data, such as the information in electronic health records, to measure the outcomes of care.

*Please note that in January 2022, PCORI merged the Pragmatic Clinical Studies and Broad funding opportunities into the renamed Broad Pragmatic Studies, which will simplify the PCORI submission process for applicants, reduce confusion about which funding opportunity is most appropriate for a given study, and assist applicants in their long-range research planning. Learn more here

Methodology Studies

Improving existing PCOR and CER methods will benefit patients, caregivers, and clinicians in making healthcare decisions. PCORI’s methodology studies provide results that guide researchers in planning future studies, and also can help policy makers weigh the value of research results. Understanding the design of a study is critically important to determining the usefulness of its findings. To be trustworthy, findings must use valid, rigorous, patient-centered methods. The PCORI Methodology Standards and PCORI Methodology Report provide specific guidance on how to design and carry out research. Our methodology research program provides new insights that help improve this guidance.

We are interested in funding studies on topics including the following:

  • Methods for improving the sources of data used in PCOR
  • General and design-specific analytical methods
  • Issues related to human subject protections


To improve the nation’s capacity to conduct PCOR and CER efficiently, we are supporting the development of a large, representative, national clinical data network. This data infrastructure—known as PCORnet, the National Patient-Centered Clinical Research Network—fosters a wide range of experimental and observational patient-centered studies. Patients and other stakeholders are participating in implementing network activities. The goal of PCORnet is to improve the pace, quality, and patient-centeredness of clinical research.

Research on Rare Diseases

We aim to fund patient-centered CER that addresses outstanding questions about the prevention, diagnosis, and treatment of rare diseases. PCORI’s authorizing law calls for a focus on these conditions, defined as those affecting fewer than 200,000 people in the United States. We have developed guidelines to advise the community on the types of rare disease research we fund.

Posted: September 10, 2014; Updated: March 22, 2021

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The Patient-Centered Outcomes Research Institute sends weekly emails about opportunities to apply for funding, newly funded research studies and engagement projects, results of our funded research, webinars, and other new information posted on our site.

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