Lying with Numbers

I've gotten feedback on "why quantitative measures are better", and how statistics provide a firm footing for higher-order discussions in our field.  Bullocks.

"There are three kinds of lies: lies, damned lies, and statistics." 
-Attributed by Mark Twain to Benjamin Disraeli, but actual source unknown

Gentle reader, please don't get sucked into the mythology of numbers.  I once was working with a veneer cutting laser system that was supposed to yield a 5-10% improvement in optimization of raw materials (which, if you've priced exotic hardwood veneer, you'll know that 1/4" of the really high-end stuff is about $.25, so gaining 1/4" on 5000 cuts a day really adds up).  After three days, the customer was yelling that our equipment was flawed and not calibrated correctly, because their waste scrap had gone UP not down.  

It turns out that the measurements were precise, but humans were gaming the system.  Through observation, we found substantial staff resistance to change had thwarted our efforts - they would take a precise measurement using the laser measuring systems, and then round up 1/4" to 3/8", just as they always had when using a measuring tape.  However, the human system meant that a 1/4" of rounding was actually barely sufficient sometimes, and was on a bell curve where the initial measurement was fractionally short.  

Why it had gotten worse was because, with precise measurements by lasers, the bell curve was flattened into a tight plateau.  The entire rounding padding added by the cutting staff was scrap, since the laser cutter was never "too short".  Precision of laser measurement had been confused with accuracy, and a sampling bias had created a substantially deviant wrong answer with high precision.  Once we got the staff to only round up 1/100", the customer got all the savings they had forecast, and the scrap pile was nothing but sawdust. (In the Hollywood version, I probably would have gotten a mahogany and teak inlaid armoire in appreciation.)

Yes, numbers can DEFINITELY lie, because the context gets twisted.

You have to look VERY carefully at what the number is reporting.  So, if you'll indulge me, let me tell the truth, while providing misleading statistics that would enable me to lie.

Example: You're picking participants for a research project, and you want to include a person with little experience in their field, and a person with a lot of experience.

Given the following, who do you choose?

1. Amanda's full-time experience spans 3 decades.
2. Bob has worked as a security guard for the Archdiocese for 32 years.
3. Chris logged 300,000 miles this year as a trucker.
4. Doug was Police Chief in Columbus for 15 years.
5. Emily served as a judge for 27 years.

In order, who had the most experience, from least to most?

------

you know how this works.

I have to add space.

If I don't, your eyeballs will immediately jump to the answer.

------

So, examine the statistics provided carefully, then see if you agree...

1. Amanda's full-time experience spans 3 decades.
2. Bob has worked as a security guard for the Archdiocese for 32 years.
3. Chris logged 300,000 miles this year as a trucker.
4. Doug was Police Chief in Columbus for 15 years.
5. Emily served as a judge for 27 years.

In order, who had the most experience, from least to most?

Answer:

Chris, Emily, Bob, Amanda, Doug.  (3, 5, 2, 1, 4)

How?

1. Chris is a trucker, hired this morning, and helped organize the records for the company today, documenting 300,000 miles of travels for the company.  It took her an hour to log those trips.
2. Emily has been judge of the church bake competition for 27 years.  This takes her an hour a year at the annual church picnic.  She has 27 hours experience, 27x more than Chris.
3. Bob works as security guard for the annual Archdiocese Casino Day fund-raiser, watching the cash box.  He has 32 days experience spread across 32 years, more than 25x more experience than Emily.
4. Amanda has 12 years experience, from 1999-2011, even though, on first reading, you might think she has 30+ years.  Her experience spans 3 decades, the '90s, '00s, and '10s.
5. Doug has 15 years experience as Police Chief, working 42 hours a week, for 15 years full-time experience.

I point this out, because I've seen these kinds of statistical lies in my career.  :-)