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How to explain UHU from UFOs to your city manager News

November 8, 2012

Asking the Big Questions
by Fitch & Associates

How to explain UHU from UFOs to your city manager

UHU is always calculated as the number of transports divided by the total number of unit hours in the measurement interval

By Fitch & Associates

"My City Manager doesn't know UHU from UFOs. Is there an easy way to explain it?"

Chances are you're dealing with someone who's not intimately familiar with the operations of an EMS system, so before you get into the details of what UHU is, explain why it exists in the first place — to have a standardized, shorthand way to measure workload levels in your system and to allow comparison to other systems.

UHU, or unit hour utilization, itself is fairly straightforward. It's calculated by dividing the number of transports by the number of "unit hours," with one unit hour defined as a fully equipped and staffed vehicle in your EMS system. If your system has 10 ambulances around the clock, there are 240 unit hours in a 24-hour period. If those 10 ambulances do 120 transports in 24 hours, you would calculate your system's UHU as follows:
120 transports/240 unit hours = .5 UHU

Of course, many systems vary staffing levels to meet demand, and UHU is typically measured over longer intervals than 24 hours — but UHU is still calculated as the number of transports divided by the total number of unit hours in the measurement interval.

The higher the ratio, the more productive the system, in the sense that you're getting more transports out of fewer ambulances. Measuring UHU also helps an EMS system match the number of on-duty units [supply] that are required to achieve response times [demand].

If your city manager's eyes are glazed over at this point, a comparison to something familiar might be useful. For example, if your local UPS service uses 10 trucks to deliver 100 packages in an hour, it would less productive than a FedEx service that uses 5 trucks to deliver the same number of packages in the same hour, all things being equal.

To fully benefit from using the UHU benchmark, there are a number of modifiers that must be considered. Each of the following could skew a system's UHU:

Population and call density: For example, an urban community with short transport distances will have a significantly different UHU than suburban or rural services.

Geography: Road condition and layout, traffic congestion, bridges and other factors can affect the comparison value of UHU. An EMS system in a city where roads are well laid-out and traffic flows freely will likely experience higher UHU than an similarly EMS system in a city with decaying infrastructure, inefficient routes and traffic congestion.

Time-on-Task: This measurement, the time it takes to completely manage each incident, varies and has to be considered to have an accurate UHU. For example, if crews cannot quickly offload patients at receiving hospitals because of bed availability, paperwork or other issues, time-on-task increases.

Scheduling: Shift patterns and crew scheduling practices can also influence a system's UHU. Typically, shorter shifts can tolerate higher UHU than 24-hour shifts, where high usage coupled with little opportunity for rest could increase risk.

The goal is to fully balance and optimize these variables along with clinical factors, response times, employee satisfaction and fiscal realities.

Accurately measuring UHU helps EMS leaders demonstrate that their systems are providing the community exceptional value — or defend their budget if need be. If your city manager doesn't understand UHU, you're missing an important opportunity to make your case.

About the author

For more than three decades, the Fitch & Associates team of consultants have provided customized solutions to the complex challenges faced by EMS agencies of every size and service model, both private and public. From system design, objective review and competitive procurements, to comprehensive consulting services, Fitch & Associates helps communities ensure their emergency services are both effective and sustainable. For ideas to help your agency improve performance in the face of rising costs, call 888-431-2600 or
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Kevin Haines Kevin Haines Friday, November 09, 2012 9:57:28 AM Another term that will come into play in the near future is total commit time. This is very similar to time on task, but it includes all commit times. Time committed out of service to swap a rig out, for training, for administrative meetings, etc... While it is extremely efficient to run 100 calls with 5 rigs instead of 10 what is your total commit times on those rigs? You may find that you are a whole lot less efficient for the second or third call in that area. Especially if static deployed. Great article!
Dan Greenhaus Dan Greenhaus Tuesday, November 13, 2012 5:27:52 PM And what numbers indicate that the city should have more units? For example, if the standard is 0.5 UHU, and your agency is operating at 1.8 UHU, maybe your city manager should budget to have more units? Also, if your UHU is 0.5 between 2am and 9am, and 2.2 between noon and midnight, maybe it's a sign that more units need to be funded by the city manager, especially when they complain about response times being too great.
Drew Wheresmyclipboard Posner Drew Wheresmyclipboard Posner Tuesday, November 13, 2012 5:44:55 PM unfortunately cities don't want to pay for morw ambulances. Then they merge with fire departments and you get the shenanigans of DC or EMSA
Skip Kirkwood Skip Kirkwood Wednesday, November 14, 2012 3:01:01 AM UHU doesn't capture workload very accurately, and doesn't compare between jurisdictions, because it only measures transports/unit hour. There is so much more to EMS than transports per hour. Even if you use dispatches per hour, what about posting, move-ups, unit switches, etc? And it totally depends on cycle time - if your typical call takes 35 minutes (like in a dense city with lots of hospitals), you can do a lot higher UHU than a remote area where a call takes 2-4 hours. You need good CAD data for everything if you want to measure "busy-ness." And remember that paying people for "rest" and otherwise not to work is contrary to everything a city manager believes is right.
Bruce A Mills Bruce A Mills Wednesday, November 14, 2012 3:16:42 AM Skip can you explain Time on task vs UHU ? Is there a difference or just word play?
Skip Kirkwood Skip Kirkwood Wednesday, November 14, 2012 3:41:56 AM As originally defined, UHU = transports per unit hour. Some agencies have changed this to equal dispatches per unit hour (UHUd). Time on task = how long you are busy at work - includes dispatch through "clear," plus "move to post" + "at post" plus other "work minutes." We have units, for example, whose UHU = .12, but their "busy time percentage" is .65 - they spend a LOT of time moving to and covering other posts. UHU was intended to be a measure of efficiency, not of employee workload.

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