The Hidden Threats of Obstetrics: The July Effect

Welcome to part one of our ‘Hidden Threats’ series, where we summarize some of the latest research regarding medical errors and structural issues that can impact the quality of patient care, both in obstetrics and in medicine generally. Every two weeks, we’ll be providing a short summary of the latest trends, research articles and news that patients may want to know about the way they get their healthcare. This week’s focus is the July Effect.

The July Effect - Hidden Dangers of Summer Medical Care

Summer Medical Care and Malpractice: The July Effect

In the US, July is the month when recent medical school graduates become residents and all current residents move up one year in their rotation. This ‘cohort turnover’ occurs when where the influx and outflux of entire classes of people mean a precipitous shift in the organization’s knowledge and skill. This results in:

  • A drop in the experience of healthcare providers in the hospital’s system (5).
  • A decrease in the number of doctors who know how the hospital system works and should work (5).

Functionally, this means an influx of new and untested medical staff unfamiliar with hospital protocols and procedures – and, most importantly, an increase in the rate of medical errors.

Hotly-Debated Impacts of New Residents on Medical Care

It is a well-known fact that medical errors decrease with greater experience. The same holds for medical care. As residents learn more about the units they are doing rotations in, they become comfortable with that unit’s processes and procedures. The older the residents are, the more well-trained they typically are in their roles. For example, assembly time for hysteroscopies improves with each subsequent residency year – the oldest residents were able to complete the procedure the most quickly. (1)

New Residents, More Mistakes

What does this mean for patients? Residents must practice to achieve competency, just like in any other field. The problem? Residents practicing healthcare are dispensing care that impacts human lives. Errors matter. Ostensibly, residents are always supervised by an older, fully-trained attending physician, but short-staffing (especially during night shifts, weekends, and holidays) may mean that may not always be the case. (2) Newer residents mean greater errors, and greater errors translate to higher risk of adverse outcomes, up to and including greater mortality risk.

July Effect Widespread

The Hidden Threats of Obstetrics: The July Effect Recent analyses looking at specific outcomes find that the July effect is widespread, impacting multiple areas of practice in medicine. One study that looked specifically at teaching hospitals (ie, hospitals that train medical residents) found that fatal medication error rates spiked a whole 10% in the month of July – and in no other month (3). Further, this impact did not occur in counties without teaching hospitals, suggesting that these fatal medication errors are attributable specifically to the July effect. The greater the amount of teaching hospitals in that county, the larger the spike. However, the July effect is not confined to only medication errors – it has also been found reflected in higher complication rates for severely injured patients in teaching hospitals versus in nonteaching hospitals (4, 5), and in less efficient handoffs to the next shift (5).

Possible Reasons for the July Effect

There are many possible reasons for the July effect, including:

  • Lack of experience working with patients
  • Unfamiliar work environment
  • Frequent paging during patient interaction or data entry
  • Inefficient handoff or information transfer
  • Long work hours
  • Lack of supervision, teamwork, and active discussion of errors (6)

Unfortunately, it can be difficult to pinpoint the exact cause of the July effect. Some of the above factors can be mitigated with systemic, organizational or bureaucratic changes. Heightened supervision of medical interns and residents by attending physicians is a key factor in helping medical residents understand, correct, and reduce errors.

What Should Patients Know About the July Effect?

The July effect is confined to teaching hospitals – hospitals that participate in teaching the next generation of medical professionals. Teaching hospitals can also have excellent healthcare services. Patients who are being treated in teaching hospitals should be aware, however – they might be treated by a resident physician (a doctor who finished medical school, but is not yet fully trained). These doctors are generally supervised by attending physicians (doctors who are fully trained), or by more experienced residents.

If at any point you are uncomfortable with your care, it is your right as a patient to ask what your physician’s experience level is. If they are a resident, you can ask to see the attending physician for a second opinion. It may be helpful when you are first entering the hospital system to ask medical staff what their roles are so you can orient yourself around the various providers coming in and out of the room.


  • Tam MT. Building a Hysteroscopy Curriculum in an Obstetrics and Gynecology Residency Program. Poster Presentation.
  • Gallego et al. Insights into temporal patterns of hospital patient safety from routinely collected electronic data. *Health Information Science and Systems 2015, 3(Suppl 1):S2 content/3/S1/S2
  • Phillips et al. A July Spike in Fatal Medication Errors: A Possible Effect of New Medical Residents J Gen Intern Med 25(8):774–9
  • Claridge et al. The “July phenomenon” and the care of the severely injured patient: Fact or Fiction? Surgery Volume 130, Number 2, 376 – 53.
  • Young JQ et al. “July Effect”: Impact of the Academic Year-End Changeover on Patient Outcomes: A Systematic Review. Ann Intern Med. 2011;155:309-315.
  • Shweta Chopra et al. Applying Lean Principles to Mitigate the “July Effect”: Addressing Challenges Associated with Cohort Turnover in Teaching Hospitals. Journal of Technology Management, and Applied Engineering Vol 31 # 4