photo of blue puzzle pieces that has some pieces put together but is missing many piecesThe Joint Commission shared a blog post that highlights sentinel events reported in ambulatory care. The Joint Commission analyzed data submitted between 2005 through the first half of 2019 (approximately 12,000 sentinel events) and determined that seven percent stem from ambulatory care settings. While analyzing sentinel events that are voluntarily reported to the Joint Commission helps us understand patient safety risks, it doesn’t tell the full story. Comparing this information to data in the Comparative Benchmarking System (CBS)—which represents 30 percent of all US medical professional liability (MPL) claims—it seems that the Joint Commissions number (seven percent) could be misleading as to the potential patient harm that can occur in ambulatory settings.

Looking at a slightly different time frame of 2009 through 2018, CBS data has 48,015 medical malpractice claims that were brought forth as a result of death, permanent harm, or severe temporary harm (a similar comparison to Joint Commission sentinel events). Of those claims, 45 percent occurred in ambulatory care.

Analyzing CBS provides a broader and deeper view of events that cause potential harm. Our data identify main drivers of ambulatory-related MPL claims as:

  • 29% diagnosis-related
  • 27% surgical treatment
  • 26% medical treatment

The Joint Commission further highlights the fact that wrong-site events and retained foreign objects are drivers of the seven percent of reported ambulatory sentinel events. While these are important to understand and address, CBS identifies significant top injuries alleged in ambulatory-related MPL claims as:

  • 14% malignancy (missed or delayed cancer)
  • 7% adverse reaction to medication
  • 6% puncture/perforation

Based on these data, we see diagnosis as a significant area of concern and focus for improvement in ambulatory care.

A deeper dive into diagnosis-related claims

All clinicians are dedicated to providing safe care. But they are human and working with imperfect systems. Information can slip through cracks or systems can breakdown. Occasionally, things can go wrong and lead to patient harm. This is devastating for the patient, as well as the clinician.

In 2014, we published the CRICO Strategies CBS Report, Malpractice Risks in the Diagnostic Process. This study identified diagnostic error as a top concern in ambulatory care. A more recent study conducted with researchers from Johns Hopkins University School of Medicine and funded by the Society to Improve Diagnosis in Medicine (SIDM) drilled into diagnosis-related medical malpractice cases in CBS. The study (“The Big Three”) analyzed cases from 2006-2015 and found the top three drivers of high-severity diagnostic error cases were:

  • 38% cancer
  • 23% cardiovascular events
  • 14% infection

More important than recognizing what is occurring, is to understand why alleged patient harm is occurring. Our coding taxonomy applied to each medical malpractice case captured in CBS helps shed light on this. In “The Big Three” study, the top drivers (or contributing factors*) were:

  • 86% clinical judgment
  • 35% communication
  • 22% clinical systems
  • 21% documentation

We are able to further drill down into each contributing factor category to better understand the drivers of harm. Some of the detail captured in the above contributing factors include:

Clinical Judgment


Clinical Systems

  • Failure or delay in ordering a diagnostic test
  • Narrow diagnostic focus with failure to establish a differential diagnosis
  • Failure to appreciate and reconcile relevant symptoms, signs or test results
  • Failure in provider-to-provider communication about the patient’s condition
  • Other patient-to-provider communication failure
  • Patient did not receive results—no report, or wrong report
  • Failure to follow up a new finding
  • Failure or delay in completing a recommended diagnostic test


This deeper understanding of the drivers of patient harm as seen through malpractice claims informs health care leaders and clinicians about implementing high-yield patient safety and quality improvements. For example, understanding that there is a breakdown in patients receiving test results could prompt leaders to assess the organization’s systems to assess its test referral process.

Learn More

To learn more about the data and learnings from “The Big Three” study, watch a recording of a recent webinar.

*A claim may have more than one contributing factor associated with it.

Written By
Katy Schuler, MSc
Katy Schuler was the Marketing Manager for CRICO Strategies.
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