A float pool is a unit with no floor of its own

A float pool is a staffing unit whose members have no permanent assignment and are placed each shift onto whichever unit needs them, so that short-term gaps are covered by the hospital's own people rather than by agency.

The name is literal: the staff float. On a Monday a float pool nurse might work medical-surgical on the fourth floor; on Tuesday, telemetry on the second. Her employer is the hospital, her manager is usually the staffing office or a dedicated float pool manager rather than a unit manager, and her schedule is a set of shifts with the unit filled in on the day, sometimes the night before, sometimes at the start of the shift itself.

A float pool answers a problem every unit has and no unit can solve alone. Each unit is staffed to its expected workload, and the expected workload is wrong on a third of days: somebody calls in sick, the census jumps, a patient turns out to need one-to-one care. A single unit cannot hold spare nurses for that; they would stand idle on the other two thirds of days. Pooled across twenty units the variance mostly cancels, and a smaller number of spare nurses covers all of it. That arithmetic is the whole justification.

Float pool is the common term in North American hospitals. The same idea appears as a resource team, a staffing pool, a flex team, or in the United Kingdom as a nurse bank, which is usually a per-shift arrangement rather than a salaried one.

The same clinical work as a unit nurse, on a different unit each shift, with the added skill of arriving somewhere at 07:00 and being safe by 07:15.

Floating is a genuine specialty, though it is rarely called one. A float nurse has to know where the supplies are on six units, how each one hands over, which charge nurses want to be asked and which want to be told, and how to take a full assignment on a floor she last worked three weeks ago. Good float nurses are experienced, adaptable and unbothered by not belonging; new graduates are generally not placed in the pool, because the pool is where the support of a familiar team is thinnest.

In return the role usually pays a differential over the unit rate, offers more control over which shifts are worked, and gives the nurse breadth that a single unit never would. Many nurses use it deliberately: a few years floating is a way to see every unit before choosing one, or to keep a broad skill set that a specialty would narrow.

As big as the gap it has to cover, measured from your own data rather than from a rule of thumb, and sized to the typical short day rather than the worst one.

The measurement is simple and most hospitals have never done it. For each unit, for each shift, over at least a quarter, count the hours that were short: filled by agency, filled by overtime, filled by a floated unit nurse, or not filled at all. Add them up by day. The result is a distribution, and it has a shape: most days a little short, a few days badly short. A pool sized to the worst day stands idle most of the quarter; a pool sized to the median day covers most of the gap at a fraction of the cost and leaves agency for the tail, which is what agency is for.

The number that comes out is in hours per day, and it converts to people the same way any establishment does: hours divided by the productive hours in a full-time equivalent, multiplied by a relief factor for the pool's own leave and sickness. A float pool is a unit for staffing purposes and is short by its own leave entitlement if the relief factor is skipped, exactly like any other unit. The nursing FTE calculator linked below does that arithmetic.

The one thing the measurement will also show is whether the gap is variance or vacancy. A unit that is short every single day is not short by chance; it is under-established or unfilled, and a float pool that covers it permanently has become that unit's staffing at a differential. Sizing the pool honestly means fixing that separately.

Two schedules, not one: the pool's own roster, which says who is working which shift, and the daily placement, which says where. The second is where the work is.

The pool's roster is an ordinary unit roster: shifts, rotations, rest gaps, weekends, the usual rules. What makes it different is that every shift is placed on the day. The staffing office looks at the morning's gaps, the pool's competencies, and who floated where yesterday, and matches them. Done by hand, that is a whiteboard and a phone at 05:45.

Competency is the constraint that matters. A pool is really several pools: the nurses cleared for critical care, the ones cleared for telemetry, the ones cleared for medical-surgical only. A placement that sends a nurse to a unit she is not competent for is unsafe, and a schedule that does not know the difference will do it under pressure. The same is true of credentials: a float nurse's licence and certifications have to be valid on every unit she could be sent to, which is a stricter test than for a nurse who never leaves one.

The fill order is the other rule. When a shift opens, the cheapest safe fill is a nurse already employed on that unit, then the float pool, then a nurse from another site in the same organisation, and only then agency. MedAligna schedules the pool as per diem staff with no home location and offers an open shift in that order, own staff first, float pool second, another location third, agency last, with every candidate checked against the unit's credential and rest rules before she is offered it. A tool that jumps to agency because it is the one button that always works is the expensive kind.

Experienced nurses who like variety and can walk onto a strange unit and be useful; not new graduates, and not nurses who need a team to feel safe.

Hospitals suit it when they have enough units of similar type that a nurse can genuinely move between them; a specialty hospital with three very different units has less to pool. Systems with several sites can go further and float across buildings, which is the sister-site tier of the same idea.

For the nurse, the question is what she wants from work. Floating trades belonging for breadth, a fixed team for a differential, and predictability of place for control of time. Some nurses find that the best job in the hospital and stay in the pool for a decade. Others last a year and take a home unit with relief. The units that run a pool well are the ones that ask, and that let a floater leave the pool without it being a demotion.