In the mood for a good laugh? You know, sometimes the City of Dallas can be its own worst enemy.
We have referred previously to a city-prepared Microsoft Powerpoint presentation being used to promote the city's "Verified Response" proposal. Under Verified Response, the police department would no longer respond to burglar alarm calls unless a crime-in-progress were verified by someone such as a security guard or neighbor.
Though the city's presentation lacked many details it really needed, an interesting statistic jumped out of it: the Dallas Police Department's calculation showing that police officers average 4.4 "active work" hours per 8 hour shift.
"Active work," according to the City Manager's office, is the amount of time a police officer averages on the street actually answering calls and enforcing the law.
To a statistics misfit (like me), this statistic screams: "take a closer look."
Most every reader of Dallas.Org knows that some of our claims-to-fame are our online salary databases. It may be the reason why you are reading this article right now.
One of the nice things about hosting these kinds of databases is that information is literally at your fingertips.
So I did a little number crunching to put this statistic in perspective. Follow along with me, and we'll do the math together.
According to the City of Dallas, there are 35 police corporals, 93, police lieutenants, 1,028 police officers, 1,171 police senior corporals and 397 police sergeants.
There are others in the police department: apprentice officers, probationary officers, trainees, captains, deputy chiefs and the chief. I decided not to include these positions in the statistics. This isn't to say that these folks don't do "active work."
Rather: hey, let's be conservative with our figures!
Next, let's make some assumptions. Let's assume a 40-hour work week. The City bases it's figures on 4.4 active hours per 8 hour shift. This would imply that, if you take 5 of these shifts per week, you get 40 hours.
Everybody gets a two week paid vacation and some paid sick leave. So let's base our calculations on a 49-week work year (as opposed to 52).
So let's start doing the math:
- 35 + 93 + 1,028 + 1,171 + 397 = 2,724 FTE's (full time equivalent police officers)
So we've decided each one of these folks will average 49 weeks a year (which we've been told is low, but we're being conservative here). So here's the math:
- 8 hours-a-day X 5 days = 40 hours-a-week
- 40 (hours) X 49 (weeks) = 1,960 hours-per-year for each FTE
So now let's do the math and put it all together:
- 2,724 people X 1,960 hours = 5,339,040 total hours per year
Does that make sense so far? OK, now for the hard part. The city's Powerpoint presentation says that the DPD bases it's calculation of lost time answering alarm calls (47,000 police officer hours) on 4.4 active hours per 8-hour shift. It also places the cost of those 47,000 hours lost at "$3.485 million dollars."
Again some handy math:
- 4.4 (hours) / 8 (hour shift) = 55%
So 55 percent of a police officer's time (24 minutes over half an 8-hour shift) is spent actively enforcing the law or answering calls. By doing subtraction (100 - 55), we find that 45% of an 8-hour shift is "inactive" time.
And:
- $3,485,000 / 47,000 (hours lost) = $74.15 net cost-per-hour lost
Following so far?
So let's apply this 45% "inactive time" figure to the 5,339,040 total hours per year and see what this translates to in hours:
- 5,339,040 (total hours) X .45 = 2,402,568 "inactive" hours per year
Everybody grab a calculator and make sure we didn't make any math errors. Makes my head hurt, but assuming we didn't that translates to 2.4 million "man hours" a year doing something other than enforcing the law.
Hey, hang with me here. This is where it gets interesting.
With the help of a friend of mine, a Dallas Police senior corporal with years of experience, we commissioned a study. He's asked to remain nameless, and I'll probably honor the request. Oh, I may "out" him someday for my own amusement. But that's the risk you take hanging around with a gadfly!
So after much scientific research, we discovered that the average bathroom break takes about 7 minutes. A healthy, non-coffee-drinking police officer (without medical conditions that would contribute to skewing the average), takes 3 of these breaks a day.
A coffee drinker (again, without contributory medical conditions) takes approximately 5 breaks a day--averaging 2 more than their non-coffee-drinking counterparts. Our scientific research (which, like the City of Dallas, we're not going to release details) further concludes that 80% of all police officers drink coffee.
So let's pull out the calculators again.
- 2,724 (total officers) X .80 = 2,179.2 officers who drink coffee
- 7 (minutes) / 60 (one hour) = .116 hours per break
- .116 (7 minutes per hour) X 2 = .232 excess hours lost per shift, per coffee-drinking officer
We continue on:
- .232 (14 minutes per hour lost) X 5 shifts per week = 1.16 hours per week
- 1.16 (hours lost) X 49 weeks (the average work year) = 65.93 hours lost to drinking coffee
- 65.93 (excess hours) X 2,179.2 (coffee drinking officers) = 143,674.65 hours wasted
Now remember that $74.15 net-loss figure we computed based on the city's calculation as to how much revenue were wasted by false alarms? Let's apply that:
- $74.15 X 143,674.65 (excess hours required by coffee-drinking officers) = $10,653,475.30
So while the City of Dallas loses $3.485 million in revenue responding to false alarms, it pales in comparison to the $10.6 million dollar impact that coffee has on officer productivity.
Personally, I want the City to do something about this before taking up the issue of Verified Response.
What does 2+2 equal? Ask a mathematician, and she'll say "four." Ask a statistician and she'll say "what do you want it to be?"
Ain't math fun!
Editor's Note:
About 10 minutes after this article went up, I received an email: "you can't be serious?" Of course this isn't serious! It's intended to show that numbers can be twisted around into anything you want them to be. The $3.485 million figure produced by the city as "lost revenue" due to false alarm calls is no more valid than our $10.6 million due to potty breaks.
One statistic that is interesting is the "2,402,568 'inactive' hours per year" number. This probably deserves a little closer look.
For instance, if it really is the case that 45% of a police officer's time is not spent enforcing the law, an easier way to put more crooks behind bars is to reduce this percentage (translation: find ways to increase the 55% time a police officer does spend enforcing the law).
But I have a feeling there's more to this figure than meets the eye here too.
One thing for certain: the Verified Response issue has people talking about all sorts of things!
Now excuse me. I've had too much coffee!