A String of Mistakes: The Importance of Cascade Analysis in Describing, Counting, and Preventing Medical Errors

Woolf, et al. carefully examined the complex nature of medical errors in primary care. Their method and findings demonstrate the importance of moving beyond merely counting error types to examining what happens before the final error. Among their important findings, is that differing distal errors have common proximal errors, suggesting focus areas for developing effective interventions. Their findings also highlight the critical role of communication as a precipitating circumstance and the need to improve, through systems and training, the transmission of information among clinicians, staff, and entities outside the practice.

Findings from our own quantitative and qualitative study of errors in primary care likewise showed the prominence of communication errors (about 70% of incidents).1 Like those of Woolf et al., our findings arose not from looking for “the error” to name. Rather, we thoroughly reviewed the entire incident and attempted to describe everything that seemed relevant to reported events.

We’re very encouraged to learn that their careful analysis of an incident (versus just the distal error) yielded similar findings to ASIPS—that is, multiple errors occur within a single incident, communication errors are prominent, non-clinical harm is reported, and diagnostic errors comprise a notable percentage of incidents. However, we’re skeptical that currently “more than 90% of the errors in communication appeared to be remediable by computers or other information systems.” Studies of data transfer between hospitals and PCPs found electronic systems didn’t help much;2 and a study of automated prescribing showed little change in the rates of prescribing errors.3 Certainly, the improvements in specific communication errors through improved systems is testable in primary care and merits further investigation.

We support the inclusion of non-physicians in future reporting systems. Non-physicians are willing and able to describe incidents and their cascades. This group’s perspective is especially important because they are likely to be among the sources and end-points of miscommunication. We found that office staff (especially non-clinical staff) are more likely than physicians to report incidents that have non- clinical harm, and staff report different types of errors than physicians do. Such contributions help complete the picture of errors and suggest places to focus further research and interventions.

Reference List

1. Fernald DH, Pace WD, Harris DM, West DR, Main DS, Westfall JM. Event Reporting to a Primary Care Patient Safety Reporting System: A Report From the ASIPS Collaborative. Ann Fam Med 2004 Jul;2(4):327-32.

2. Forster AJ, Murff HJ, Peterson JF, Gandhi TK, Bates DW. The incidence and severity of adverse events affecting patients after discharge from the hospital.[comment]. Ann Intern Med 2003 Feb;138(3):161- 7.

3. Gandhi TK, Weingart SN, Borus J, Seger AC, Peterson J, Burdick E, et al. Adverse drug events in ambulatory care. N Engl J Med 2003 Apr;348(16):1556-64.

Competing interests:   None declared