The costs of medical error in Massachusetts

Medical errors remain frequent, harmful, and costly.

In 2019, we released our first study of medical harm in Massachusetts that found almost 62,000 patient harm events in one year and estimated the cost to payers at a very conservative $617 million. Since then, costs have risen and researchers have found that, in hospitals, about one in four patients experience harm events during their admissions. These findings allow us to calculate the annual cost of patient harm events in Massachusetts hospitals with a high degree of confidence. We estimate: 

• 179,478 patients experienced at least one harm event during their hospitalizations;
• Health plans paid $2.14 billion in excess claims for additional care necessitated by the harm, at least $446 million of which was paid by MassHealth.

These figures do not include costs to patients and families and to the hospitals themselves. Nor do they capture how harm events impact patient and workforce well-being and strain system capacity. 

Read the updated report