A structural calculation error embedded in nursing workforce planning textbooks, government frameworks and credentialing programs since at least 1960 may be causing hospitals to systematically underestimate the number of full-time equivalent nurses they need to budget, according to an April 17 analysis published by nursing informatics specialist Robert Wingo, BSN, RN.
Here are four things to know.
1. The error is in the formula hospitals use to convert patient care staffing needs into total FTE budgets, Mr. Wingo said. The correct method divides patient care FTEs by the patient care percentage to calculate the total workforce needed. The common practice — documented across textbooks, credentialing programs and government frameworks — multiplies the patient care base by the nonproductive rate and adds the result. The multiplication method accounts for leave coverage of bedside nurses but fails to account for the leave time of the coverage staff themselves, producing a compounding shortfall.
2. The gap is significant enough to affect operations but small enough to have avoided detection for decades, according to Mr. Wingo. At a 20% non-productive rate, the multiply method applied to 80 patient-care FTEs produces 96 total FTEs instead of the correct 100 — a four-FTE shortfall per 100 before the fiscal year begins. In hourly terms, that gap translates to 160 hours of coverage per week that were never planned for or funded. Scale that to a 500-FTE nursing department and the shortfall grows to 20 FTEs.
William Ward Jr., associate professor of health finance and management at the Johns Hopkins Bloomberg School of Public Health, identified the same structural problem in his 2016 textbook, Health Care Budgeting and Financial Management, writing that the common approach will always produce a budget with insufficient staff.
The correct formula, Mr. Wingo said, is: total FTEs equals patient care FTEs divided by patient care percentage.
3. Mr. Wingo has documented the error in more than 30 sources spanning at least 66 years. He traced the earliest confirmed instance to a 1960 monograph by Sister Mary Laura Gunn, published by the Catholic Hospital Association and endorsed by the director of the department of hospital administration at St. Louis University. The error has since appeared in U.S. nursing finance textbooks, continuing education programs, consulting materials, professional organization publications and government frameworks in the U.K., Europe, Saudi Arabia, New Zealand and Australia. The error gained fresh visibility when the Western Australia Department of Health used the nurse staffing ratio framework in a mandatory healthcare staffing law implemented in February.
4. The staffing implications could lead to clinical consequences, Mr. Wingo noted. Numerous studies have identified links between nursing staffing levels and patient outcomes. A landmark U.S. study published in The New England Journal of Medicine in 2011 found a significant association between below-target nurse staffing and increased patient mortality, and a 2024 University of Pennsylvania study of 6.5 million Medicare patients found that a 10% reduction in registered nursing staff raised the risk of patient deaths by 7%.
Mr. Wingo is a nursing economics fellow with the Commission for Nurse Reimbursement, a U.S. nonprofit launched in 2023 to reform how nursing care is financed.
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