Healthcare managers are faced with the double challenge of distributing nursing assignments equitably and ensuring quality patient care.
Although giving each nurse the same number of patients may seem like the best course of action, it may result in uneven workloads or patient assignments that are not ideally matched with nurses’ expertise.
Due to the inherent complexity of nurse staffing, many leading nursing organizations recommend that staffing practices be based on patient acuity.
What is acuity-based staffing?
Acuity-based staffing is a model for determining the appropriate number of patients per nurse based on the patients’ acuity. Patient acuity is determined by the severity of the patient’s condition and the intensity of registered nursing care the patient requires, measured in hours per patient day (HPPD).
Patient acuity—along with nurse preparation and autonomy—is an essential factor in achieving appropriate workload distribution.
How common is acuity-based staffing?
Based on “Nurse staffing legislation: Empirical evidence and policy analysis” and recent data from the American Nurses Association, 16 states currently have some form of nurse staffing legislation.
- California and Massachusetts have mandated nurse‐to‐patient ratios for hospital units. (Massachusetts only has mandated ratios for intensive care units.)
- Illinois, New Jersey, Rhode Island, New York, and Vermont don’t have mandated ratios but have policies requiring hospitals to report their staffing plans and/or staffing information publicly.
- Connecticut, Illinois, Nevada, New York, Ohio, Oregon, Texas, and Washington have state-mandated nurse staffing committees at the hospital level. These committees include direct‐care nurses, nurse managers, and nursing executives who meet to formulate nurse staffing policies for their respective hospitals. Policies can include nurse‐to‐patient ratios, nurse preparation assessment, and acuity‐based staffing plans.
- In Minnesota, a Chief Nursing Officer develops a core staffing plan.
Acuity-based staffing may not be explicitly mandated, but it is an implicit consideration. For instance, nurse-to-patient staffing ratios in California hospitals are based on patient acuity: There must be one registered nurse (RN) per patient in an intensive care newborn nursery service unit but one nurse per six patients in a psychiatric unit.
Health systems should not dismiss the importance of patient acuity in guiding staffing practices.
With patients entering hospitals with higher acuity levels and being discharged sooner, nurses are at a higher risk of being assigned multiple high-acuity patients, which, in turn, may lead to missed nursing care.
How is acuity-based staffing determined?
Some hospitals or specific units may rely solely on charge nurses’ clinical judgments to determine patient acuity. Others may employ acuity tools.
Ideally, nursing staff should be involved in developing or modifying an acuity assessment tool or system. Involving staff could improve the tool’s efficiency as well as nurse job satisfaction and retention.
A study published in 2025, “Adaptation of a Synergy Model-based Patient Acuity Tool for the Electronic Health Record: Proof of Concept,” demonstrated the feasibility of adapting an evidence-based patient acuity score for automation in the electronic health record (EHR). This automated patient acuity score can help improve staffing decisions, support nursing practice, and enhance team collaboration.
These data-driven nurse staffing models may incorporate relevant staff information in addition to real-time patient acuity assessments. This integration of information helps healthcare facilities efficiently align patients’ needs and nurses’ experience, education, and skills.
Pros and cons of the acuity-based staffing model
As with any other nurse staffing system, implementing an acuity-based staffing model has benefits and challenges.
Pros: Benefits of acuity-based staffing
Here are some of the top benefits associated with acuity staffing:
- Decreased adverse events: Acuity-based staffing has been linked to decreased mortality, falls, catheter-associated urinary tract infections, central line-associated bloodstream infections, and pressure ulcers.
- Increased nurse job satisfaction: Nurses’ job satisfaction largely depends on their workload and their perceived ability to deliver high-quality care. Nurses feel frustrated when assignments are inequitable and when the workload makes quality patient care challenging. Acuity-based staffing allows for fairer workload distribution.
- Reduced costs: Acuity-based staffing has been linked to reduced overtime and overall costs per case. Nurses attribute the reduction in overtime to having sufficient time during their shifts to complete their work. Patient acuity data facilitates the accurate calculation of the required HPPD.
- Reduced lengths of patient stays: This model optimizes nurse staffing and operational outcomes. A more efficient use of resources results in decreased lengths of patient stays.
Cons: Key challenges of the acuity model
The following are some of the most significant challenges associated with implementing an acuity-staffing model:
- Subjectivity: If patient acuity is based solely on nurses’ opinions, the system would be highly subjective. Therefore, it is crucial to incorporate data-driven systems into acuity staffing practices.
- Reliance on accurate documentation and data: Accurate documentation is particularly important for effective acuity-based staffing. Inaccurate documentation could lead to inappropriate staffing due to misrepresentations of patients’ acuity levels.
- Fear of change: Staff members accustomed to specific staffing ratios may resist switching to an acuity-based system. Changing the staffing model requires involving and training staff, which implies increased resource use in the short term.
Acuity-based staffing compared to other staffing models
Depending on the state and the type of facility, other models may be more ubiquitous than acuity staffing. The following are other common staffing models.
Nurse-patient ratio staffing
A nurse-to-patient ratio staffing model determines a maximum number of patients per nurse based on the healthcare setting. For instance, in California, a nurse in a medical-surgical unit cannot have more than five patients at any given time.
Some hospitals may also routinely lower staffing ratios during night shifts or over weekends. On the other hand, facilities that use acuity-based staffing typically maintain staffing levels over these times.
It should be noted that reducing staffing ratios for night shifts has been associated with longer lengths of hospital stays.
Budget-based staffing
A budget-based staffing model determines the appropriate number of nurses by calculating the minimum number of HPPD required by patients in a given facility or unit.
This model may be most appropriate in long-term care facilities where the staffing mandate of the Centers for Medicare and Medicaid Services (CMS) requires a minimum number of HPPD.
However, even in LTC facilities, where patient acuity is typically lower, each patient has unique care needs that may not align with the minimum care hours required by law.
An acuity-based staffing model can complement federal and state requirements by ensuring patients receive the care they need and nurses are not overburdened.
Considerations for choosing a staffing model
When choosing a staffing model, healthcare leaders should consider the following aspects.
Patient
A staffing model must contemplate numerous aspects that impact patients’ care needs, including the following:
- Disease or health status
- Patient complexity
- Length of stay
- Functional status
- Activities of daily living
- Need for transport
- Age
All of these factors are critical in determining patients’ nursing care needs and the HPPD they may require.
Nurse
An effective staffing model considers the characteristics of nurses in addition to patient characteristics. Important nurse characteristics to consider include the following:
- Level of education
- Additional training
- Total experience
- Specialty or unit-specific experience
- Skills
Adequately matching patient assignments with nurses’ training and expertise can improve patient care and staff job satisfaction.
Facility
The type of healthcare facility is another factor to consider when choosing a staffing model. For instance, the CMS mandate regulates minimum staffing standards for long-term care facilities, but this mandate is not applicable to hospitals.
Hospitals have to comply with state-specific staffing legislation when applicable. Furthermore, staffing guidelines vary by unit.
For example, the RN-to-patient staffing ratio in all intensive care units in Massachusetts must be 1:1 or 1:2 depending on the patient’s acuity assessment. In this particular setting, state law determines that a combination of minimum staffing ratios and patient acuity must be considered to determine appropriate staffing.
Additional facility-related aspects that must be considered to determine the most appropriate staffing model include the following:
- Workflow processes
- Documentation expectations for nursing staff
- Physical layout of the floor
- Existing support, including nursing assistants
How to successfully implement acuity-based staffing
Healthcare facilities interested in using an acuity-based staffing model should consider the following steps and related aspects for successful implementation.
Collect patient acuity data
As mentioned, an acuity-based staffing system is dependent on collecting accurate and complete patient data. Organizations may decide to use a commercial system or develop one locally.
Commercial systems offer developed algorithms that can be adapted to the local nursing model. However, these systems may have a high data-entry burden. Furthermore, they typically focus on patient needs without contemplating the increase in nursing workload intensity associated with patient turnover.
Local systems can be custom-made to adapt to specific units or to incorporate variability the nursing staff considers important—such as patient turnover. However, if local systems are manual, the data-entry burden is significant.
Ideally, healthcare facilities should use the EHRs to automate patient acuity scores.
Establish a patient classification system (PCS)
Based on the particular patient acuity tool a facility uses, there should be a clear classification system that determines the level of nursing care a patient needs.
Patients’ care needs must align with nurses’ education, experience, and skills.
Determine staffing needs
Staffing needs may surpass availability when there is a surge in patient census or last-minute nursing staff call outs.
When staffing needs surpass available nurses, facilities must be able to adapt, relying on flexible staffing strategies to cover acuity-based needs.
For these situations, healthcare leadership should consider per diem staffing to maintain safe clinician coverage.
Train and enable your staff
When introducing a new acuity-based staffing system, shared governance and significant support are crucial for a smooth transition.
Implementation of a new system should occur slowly, and resistance to change should be identified and addressed early on.
Monitor and evaluate regularly
Regardless of the patient acuity tool a facility is using, it is important to continuously assess its effectiveness and make modifications as necessary.
Shared governance is essential so that nurses’ experiences and feedback are reflected in decision-making.
Your staffing strategy should be custom-tailored
Staffing is complex. Whether you manage a hospital unit or a long-term care facility, you may find that a single staffing model does not quite cut it.
Even if you comply with federal staffing mandates and state regulations, assessing nursing care needs based on patient acuity can help your facility provide better patient care and improve staff job satisfaction.
Aside from using patient acuity data to guide workforce management of internal staff, healthcare facilities can use this information to plan for additional nurse scheduling when needed.
When acuity-based scheduling calls for additional clinician coverage, facilities can turn to PRN staffing for customizable solutions.
Sources:
- National Library of Medicine: Adaptation of a Synergy Model-based Patient Acuity Tool for the Electronic Health Record: Proof of Concept
- Wiley: Nurse staffing legislation: Empirical evidence and policy analysis
- American Nurses Association: Advocating for Safe Staffing
- American Association of Critical-Care Nurses: Acuity-Based Staffing
- American Nurse: Practical steps for applying acuity-based staffing
- American Nurse: A new patient-acuity tool promotes equitable nurse-patient assignments
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