Real world evidence

Real World Evidence


Quick Definition

Real-world evidence (RWE) refers to clinical and economic evidence which has been derived from the analysis of real-world data (RWD).

Additional Background

RWE is important way to enable manufacturers to gain an understanding of a drug’s safety and effectiveness when taken by patients in uncontrolled settings, that are more reflective of real-world practice.

This can be beneficial in demonstrating the value of a product to regulators, payers, and health care professionals.

Unlike traditional randomised controlled trials (RCTs),

Types of RWE Studies

Prospective observational studies

  • Designed to assess predefined primary outcomes
  • Participants are not randomized; treatment is at the physician’s discretion
  • Provide some of the strongest and most valid RWE

Retrospective observational studies

  • Analyse historic data to assess specific outcomes
  • Are more likely to be subject to bias and confounding factors than prospective studies

Case studies

  • Reports on the clinical experience/treatment of a single patient

Patient registries

  • Organized systems that use observational methods to collect uniform clinical data on a population defined by a particular disease, condition, or exposure
  • Are typically prospective
  • Can collect clinical data for a large patient population and track how patients respond to particular therapies

Post-marketing studies

  • Clinical studies that pharmaceutical companies agree to conduct at the time of regulatory approval
  • Can generate additional clinical evidence such as long-term safety/effectiveness data

Cohort studies

  • Reports of the clinical experience/treatment of a group of patients, for example, at a single centres

Advantages of Real World Evidence

Less researcher involvement

Unlike traditional randomised controlled trials (RCTs), generation of RWE allows researchers significantly less involvement and control of medical management of the patient beyond observing outcomes.

Outcomes representative of the real world

The limited control of researchers can result in evidence which is more representative of clinical practice than that generated from RCTs.

Findings are more generalisable

This can often allow results to be more generalisable to a wider population of patients and can play an important role both pre- and post-product launch, aiding in regulatory approval, patient access and physician awareness. RWE studies also often include larger sample sizes and longer follow-up periods than RCTs.

Limitations of Real World Evidence

Lack of control and bias

One of the main limitations of real world evidence is the lack of control in collecting RWD. This can increase the risk of both bias and confounding factors.


In addition, quality, accessibility, transparency and extensiveness of coverage of RWD can vary significantly, requiring caution when choosing the most relevant source.


  • Benefits and limitations of real-world evidence: lessons from EGFR mutation-positive non-small-cell lung cancer, available at:

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