Service Level vs. Operating Efficiency

One of the biggest challenges in a call center, believe it or not, is when your shop is doing “too well”!

Too well?

Excuse me, but how could it even be possible to do “too well”???

Lemme explain…

The whole premise behind “queuing theory” – – how quickly do you wanna answer your incoming calls & how many agents will you need – – is figuring out how many reps need to be “available” (waiting for a call) when the next incoming call arrives.

It all depends on how many calls you receive & when (usually broken down into 15-min segments)….the length or AHT/Average Handle Time (the actual time spent talking with the customer + the off-phone “work tone” associated with that specific call)…and your desired Service Level (% of callers answered within X seconds).

There are mathematical tables available (Erlang C tables, to be exact) that will perform the calculations once provided with the required data. They’re easily available on the internet or imbedded within dozens & dozens of different forecasting & staffing software applications.

These tables were developed by the Danish mathematician, A.K. Erlang, more than 100 years ago.

But, once again, it helps determine how many agents must be available (or soon will be available) to answer an incoming call.

Availability…pure waste…is a very fickle creature & a necessary evil!

If you don’t have enough availability, your customers will wait in queue longer, resulting in a poorer Service Level (but your reps will be much busier).

Poor Service Level = unhappy customers.

But if you have too much availability, there will be fewer (or no) calls in queue, resulting in a much better (or “too good”) Service Level as your people will be less productive.

Very high Service Level = very happy customers, but very sad Finance people & bosses.

“Available” means the rep is doing nothing other than waiting for a call. But it’s absolutely essential in that the proper amount of availability is necessary to maintain your desired Service Level.

Historically, answering ~80% of your calls within a “defined acceptable waiting period”…usually, 20-30 seconds…governs the overwhelming majority of professional call centers.

Supposedly, the “80 in 20” Service Level originated in the sales industry as 20 seconds – – equates to 4-5 rings – – was considered the longest, ACCEPTABLE waiting time that a caller would tolerate.

Citi, for the most part, used a “80% in 20 seconds” as a standard. Although back in the ’80s, we had “95% in 20 secs” for Priority Service customers (the predecessor to CitiGold), though the volume was limited.

At Lehman Brothers mortgage-servicing subsidiary, our standard was “80% I n 30 secs”, a slightly-higher tolerance level vs. retail banking.

The same “80% in 30” philosophy held true at Nationwide’s Retirement Plan Services.

Now, customers will NEVER complain about an usually-high Service Level as their calls are being picked up quickly.

But a sharp boss will realize that you’re wasting money! Throwing it right out the damned window.

As mentioned, a call center is a very tough place to (try to) manage.

It’s almost “damned if you do & damned if you don’t”!

But you need to be prepared for both situations…too much availability (high Service Level) as well as not enough (poor Service Level).

Much easier said than done.

If you’re “regularly” exceeding the 80% SL/Service Level (in other words, you have “too much availability” over extended periods of time), you’ll need to reassess the assumptions that you entered into your staffing model.

Call arrival patterns by day, by 15-min intervals.

Average handle times for these calls (which can be affected by rep experience/expertise…type of calls…time of day…day of week…day of month)

If/when you adjust any of the variables in the model, it will spit out a whole different set of schedules for your staff.

It may point out the need for a greater percentage of part-time schedules to “cover volume spikes” (certain hrs of the day &/or certain days of the week/month).

Conversely, if you’re consistently failing your SL standard, you’ll need to also reassess all the variables you entered into your staffing model – – though your resultant action will be different.

The tricky part…whenever you’re not operating in the “optimal SL range” (let’s say, 80%-84%)…is to figure out if it’s a temporary condition (too much absenteeism, unscheduled training/meetings, systems issues, etc.) or whether it’s a sign that you need to look for historical patterns.

Do we have “poor SL” every Monday?Every 1st of the month? On the last day of “no late fee” mortgage payments?

Are we sufficiently staffed during our highest volume hours, e.g., 9AM-noon? What about during “traditional lunch hours”? Are we doing “too well” in the afternoons?

Call centers traditionally concentrate on Service Level to avoid going BELOW standard.

But surpassing Service Level TOO HIGH or TOO CONSISTENTLY requires just as much attention!!!

You can see which teams may need a team meeting.

Are there training needs on the floor & how many reps need to be trained?

Can you offer VTO/Voluntary Time Off (say, for the rest of the day if the person uses hours from his time-off bank or agrees not to be paid for that time)?

Is it a good time for (some) managers to do call-calibration or review sessions?

Is there some paperwork you can assist another unit with to help reduce their inventory?

Remember, doing a 100% Service Level with the minimal number of available agents is a whole lot better than doing a 100% SL with dozens & dozens reps available. Exactly “how many available reps” is the right number depends on the size of your call center (or call volume).

Many call centers who suffered from periods of poor SL are often very hesitant to ever pull someone off the phone.

But, again, you can’t do better than 100% and it’s just silly, and extremely wasteful, to not properly manage periods of excess availability…regardless of past performance!

If you notice your reps sitting around & mostly doing nothing, then speak with your Control Desk. They could be so “irrationally ecstatic” about (finally) doing 100% Service Levels that they’re not noticing all the money that’s going right out the window.

You always have to be vigilant as possible and realize that things can…and will…change quickly.

The very best call centers always pass their timeliness standards…with as little room to spare as possible!

Doing an 81% Service Level for the month is MUCH, MUCH BETTER than doing a 91% SL.

You passed the 80% standard in both cases, but your overall productivity, or efficiency, is much better at 81% than it is at 91%!

The higher the SL, the more “availability” you have & availability is WASTE!

Not much different than being a cook…not enough salt, just the right amount of salt, too much salt!

There are several masters to serve in the world of call centers…and we’re not even talking about your bosses!

That type of constant pressure is not the faint-hearted, be it the supervisory staff, the reps themselves, senior leaders or even the support staff.

After awhile, you seem to develop this “extra sense”…”How’s our Service Level”?


As always, thank you so very much for listening!

Oh, one more thing…

Regardless of how important it may be to maintain an acceptable Service Level”, NOTHING IS MORE IMPORTANT THAN WHAT HAPPENS AFTER THE CUSTOMER IS NO LONGER WAITING!!!

Yes, the actual phone call itself!

“Servicing the customer” & “managing Service Level” are 2 separate & distinct functions…they are mutually exclusive!

You NEVER change how you handle THAT customer, regardless of SL or how many customers are in the damned queue.


SL gets a whole lotta attention from senior management because it’s easily measurable.

It’s a number & there’s a standard. (It’s the “Hey, look! It’s a shiny object!” syndrome at play.)

But how well you meet your customers’ expectations is, by far, your most meaningful performance indicator…and it’s your SACRED obligation!

Good luck!

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