- OnCall Solutions Editorial Team
- Published:
When a coverage gap opens up, the instinct is to move fast. But moving fast in the wrong direction, using the wrong staffing model for the type of gap you actually have, costs time, money, and sometimes patient access.
Physician staffing agencies often help healthcare facilities compare temporary coverage models, including locum tenens staffing and flex pool staffing. Both can help maintain coverage, but they solve different problems.
The best staffing model depends on the type of coverage gap.
Flex pool staffing is often the right fit for predictable internal coverage needs: shift gaps, census swings, or short-term absences.
Locum tenens staffing is typically a better fit when a facility needs a licensed physician, APP, or specialty coverage that can’t be filled internally.
Most resilient healthcare organizations use both as part of a larger workforce strategy. Here’s what you need to know about both options and how to decide which one fits your situation.
What Is Locum Tenens Staffing?
Locum tenens staffing is a form of temporary physician staffing that brings in external, licensed providers to fill clinical gaps a facility can’t cover from within. These are credentialed physicians, nurse practitioners, physician assistants, and specialists who step in during permanent staffing gaps.
Healthcare organizations already know this model well. Locum tenens usage jumped 25% higher than anticipated in 2024, and the market reached an estimated $9.6 billion in 2025. That growth is not accidental. It reflects a workforce under real pressure.
Common scenarios where locum tenens fits:
- Physician vacancies while a permanent search is underway
- Maternity or medical leave for a key provider
- Seasonal demand spikes in high-volume periods
- Rural or hard-to-fill markets where local recruitment is slow
- Specialty coverage unavailable internally
- Recruitment gaps during onboarding transitions
- Temporary program expansion before a permanent hire is in place
The AAMC projects a physician shortage of up to 86,000 providers by 2036. For many facilities, locum tenens isn’t a stopgap; it’s a strategic necessity.
What Is Flex Pool Staffing?
Flex pool staffing draws from a pre-established group of healthcare workers who fill shifts as coverage needs arise. This pool can be internal to a single facility, shared across a regional health system, or sourced through an external vendor.
The professionals in a flex pool tend to be:
- Nurses (RNs, LPNs, CRNAs)
- Allied health professionals (lab techs, respiratory therapists, imaging staff)
- APPs (nurse practitioners and physician assistants in outpatient or procedural settings)
- Per diem staff available for as-needed coverage
- Cross-trained internal staff who can float between departments
- Regional float pools shared across multiple facilities in a health system
Flex pool staffing is designed for speed and predictability. When a call-in happens at 6 a.m., a functional pool means coverage exists without scrambling or forced overtime. In 2025, 97% of hospital systems said they planned to expand flexible work options, which is a strong signal about where workforce strategies are heading.
The Main Difference Between Locum Tenens and Flex Pool Staffing
The simplest way to think about it:
- flex pool staffing stabilizes the shift-level coverage you already have
- locum tenens staffing extends your clinical capacity when that coverage doesn’t exist internally
Factor | Locum Tenens Staffing | Flex Pool Staffing |
|---|---|---|
Best for | Physician, APP, and specialty gaps | Repeatable shift-level coverage |
Source of talent | External licensed providers | Internal, regional, or external pool |
Typical use | Vacancy, leave, specialty gap, recruitment delay | Call-ins, census changes, short absences |
Speed | Depends on credentialing and licensing | Often faster if the pool is active |
Strategic role | Extends clinical capacity | Stabilizes day-to-day coverage |
Neither model is a universal solution. Choosing the wrong one for the type of gap you have does not just create inefficiency. It can leave care teams stretched and patients waiting.
When to Use Locum Tenens Staffing
When a permanent search takes longer than expected
Physician recruitment is a long process. When the timeline slips and a position stays open for months, patient access doesn’t get the luxury of waiting. Locum tenens staffing agencies help bridge that gap by sourcing licensed providers while the permanent search continues.
When specialty coverage is unavailable internally
Some specialties simply cannot be covered from within. Whether you need a hospitalist, a proceduralist, or a behavioral health provider, a locum specialist fills the clinical role until a permanent solution is in place.
When patient access is at risk
When open positions force appointment cancellations or the sending of patients elsewhere, the calculus changes fast. A vacant physician position bleeds revenue every day it stays open. For many facilities, working with a physician staffing agency or locum tenens partner is less costly than letting the gap continue.
When existing physicians carry too much call
Overloaded physicians burn out. And burnout leads to more vacancies. Bringing in locum support to redistribute call burden is one of the more overlooked prevention strategies available. We cover this in more depth in our post on how locum tenens helps reduce physician overtime.
When a facility needs coverage in a rural or hard-to-staff market
In rural markets, local physician recruitment is often a years-long effort. Locum tenens keeps essential services available in communities that can’t wait for a permanent hire to materialize.
When to Use Flex Pool Staffing
When absences are predictable
Every facility deals with call-ins. If yours follow a pattern (weekends, holidays, specific seasons), a well-managed flex pool eliminates the scramble before it starts.
When the census fluctuates
Inpatient demand is not static. A flex pool gives your staffing model the elasticity to scale coverage up or down without defaulting to overtime or agency calls.
When overtime is rising
Forced overtime drives burnout, and burnout drives exits. Replacing one staff RN costs an average of $60,090, according to the 2026 NSI National Health Care Retention & RN Staffing Report, and hospitals are losing an average of $5.19 million per year to RN churn. A flex pool that reduces forced overtime is a retention strategy.
When departments need cross-coverage
Cross-trained staff who can float between units reduce dependency on any single staffing source. A regional float pool formalizes that flexibility.
When the organization wants to reduce reliance on last-minute agency staffing
Hospital contract labor spending has dropped from a median of 6.9% of total labor costs in 2022 to 3.3% in 2024, according to Medicare Cost Report data. That decline reflects organizations getting more deliberate about proactive coverage planning. A proactive flex pool moves the decision-making upstream, before the gap becomes a crisis.
When Healthcare Facilities Should Use Both
For healthcare leaders comparing staffing options, the question is not whether temporary physician staffing or flex pool staffing is better overall. The better question is which model fits the role, timeline, specialty requirement, and level of patient access risk.
The strongest approaches aren’t built around one coverage model. They’re built around matching the right resource to the right type of gap.
A few examples of what this looks like in practice:
- A hospital uses an internal flex pool to cover nursing gaps, while locum tenens physicians cover emergency department needs during physician vacancies.
- A health system uses flex pool APPs for predictable outpatient volume, while locum specialists cover during recruitment delays.
- A rural facility uses a float pool to stabilize daily shifts, while locum tenens providers keep essential clinical services running.
These aren’t theoretical scenarios. They reflect how healthcare organizations actually operate today, especially as improving recruitment and retention requires a layered, multi-resource approach.
How to Decide Which Staffing Model Fits Your Coverage Gap
Work through these questions before you commit to a staffing approach:
- What role needs coverage? Is it a physician, APP, nurse, or allied health professional?
- Is the gap clinical, operational, or both?
- Is the need predictable or unexpected?
- How long will coverage be needed?
- Is internal talent available to fill this role?
- Are licensing or credentialing timelines a factor?
- Is patient access at risk right now?
- Is the current care team showing signs of burnout or overload?
- Will the same need likely come up again?
If the answers point to a clinical gap that cannot be filled internally, locum tenens is usually the right call. If the gap is operational and recurring, the flex pool is the faster, more cost-effective solution. And if both are true, it’s worth building both into your coverage strategy.
One thing to keep in mind: credentialing timelines can affect the speed of locum deployment. If you’re working in a market where licensing delays are common, getting ahead of that process matters. Our guide on why credentialing delays slow hospital operations walks through what to watch for.
Building a Layered Coverage Strategy
The facilities that handle workforce pressure best aren’t always the ones with the biggest staffing budget. They’re often the ones with the clearest model for how different resources serve different purposes.
Think of it as layers. Core permanent staff form the foundation. A flex pool absorbs the day-to-day variation. Locum tenens extends capacity when internal resources run out. External staffing partners provide access to both when the organization needs to move quickly.
OnCall Solutions works with healthcare organizations to build coverage strategies that hold up under pressure. Whether you need temporary physician staffing, locum tenens support, flex pool staffing solutions, or a combination of both, OnCall Solutions can help you find the right fit.
Frequently Asked Questions
Do physician staffing agencies provide both locum tenens and flex pool staffing?
Some physician staffing agencies focus primarily on locum tenens coverage, while others support broader workforce strategies that may include APP coverage, specialty coverage, float models, or flexible staffing support. The right partner depends on the type of gap, the role that needs coverage, and how quickly the facility needs support.
What’s the difference between locum tenens staffing and flex pool staffing?
Locum tenens staffing brings in external, licensed providers (physicians, APPs, specialists) to fill clinical gaps that cannot be covered internally. Flex pool staffing draws from a pre-established group of healthcare workers to fill predictable shift-level gaps, like call-ins and census changes. The two models solve different problems and work best in combination.
Is flex pool staffing only for nurses?
No. While flex pools often include nurses and nursing assistants, they can also include allied health professionals, APPs, and other clinical staff. The pool is built around the organization’s most common coverage needs.
When should a hospital use locum tenens instead of a flex pool?
Use locum tenens when the gap requires a temporary physician, APP, or specialty coverage that can’t be filled internally. Use a flex pool when the need is recurring, predictable, and shift-based.
Can locum tenens staffing and flex pool staffing be used together?
Yes. A facility may use a flex pool for predictable day-to-day staffing needs while using locum tenens providers for physician vacancies, specialty coverage, rural access, or recruitment delays.
How can healthcare facilities reduce last-minute staffing gaps?
The most effective approach is proactive: establish a functional flex pool for predictable coverage needs, build locum tenens relationships before vacancies become urgent, and layer your coverage model so no single resource type is your only safety net.
Is locum tenens staffing a short-term or long-term solution?
Both. Locum tenens is commonly used to bridge short-term gaps during physician leave or recruitment. But many organizations also use it as a sustained strategy in markets where permanent recruitment is consistently difficult.
What is the best temporary staffing model for hospitals?
There is no single answer. For physician vacancies, specialist gaps, recruitment delays, or patient access risks, locum tenens is often the best temporary physician staffing model. Flex pool staffing is better suited to recurring operational gaps.
How do hospitals decide between locum tenens and float pool coverage?
Start with the role and risk level. If the need is for physician coverage, specialty access, or a provider vacancy, locum tenens is usually the better fit. If the need is repeatable shift coverage, a float or flex pool may be more efficient.
Ready to build a coverage strategy that works for your facility? Contact OnCall Solutions to talk through your options.