Archive for April, 2020
Business community discovers that “Experimentation Works”
Posted by mark in design of experiments on April 21, 2020
Last month the Wall Street Journal “Bookshelf” (3/15/20, David A. Shaywitz) featured a review of a book about The Surprising Power of Business Experiments.
“Tests at Microsoft in 2012 revealed that a tiny adjustment in the way its Bing search engine displayed ad headlines resulted in a 12% increase in revenue, translating into an extra $100 million annually for the company in the U.S. alone.”
Stefan Thomke, author of Experimentation Works: The Surprising Power of Business Experiments.
It’s great to see attention paid to the huge advantages gained from statistically rigorous experiments. However, vastly greater returns await those willing to go beyond simple-comparative one-factor A/B testing to multifactor design of experiments. The reason is obvious: Only by testing more than one factor at a time, can interactions be discovered.
A case in point is provided by an experiment I did on postcard advertisements. It produced a non-intuitive finding that, unlike marketers, our engineering clients preferred less colorful layouts. Knowing this, we succeeded in increasing our response at a far lower printing cost. See the proof in the interaction plot at the conclusion of this white paper on That Voodoo We Do – Marketers Are Embracing Statistical Design of Experiments.
Another compelling example of the value of multifactor testing is illustrated by website-conversion results* shown here—produced from a replicated, full, two-level factorial design.
The key to a more than 5-fold increase in clicks turned out to be the combination of going to a modern font (factor A) with a more compelling button label (C). A third factor (B), background being white versus blue, did not create a significant effect, which also provided valuable insights on the drivers for conversion.
Why settle for testing only one factor when, without investing much more time, if any, you can investigate many factors and, as a huge bonus, detect possible interactions?
*From Pochiraju & Seshadri, Essentials of Business Analytics, 2019, Springer, p 737.
Beware of birds making stick bombs in your backyard
Posted by mark in Nature, Uncategorized on April 13, 2020
One advantage of being home-bound during this COVID-19 pandemic is spending more time watching the birds. I especially like the cardinals who flock to my feeder in a variety of plumage being male, female or juvenile. However, the finches are fun to see as well, particularly the yellow ones. The other day a blue jay came by to provide a bit of blue for the color mix.
While greatly appreciating birds, I failed to recognize their superior engineering skills until reading this New York Times article about avian nest construction. They report how researchers at University of Akron used a ‘smushing’ chamber to measure how bird-homes bounce back after being compressed.
“We hypothesize that a bird nest might effectively be a disordered stick bomb, with just enough stored energy to keep it rigid.”
Hunter King, experimental soft-matter physicist, University of Akron*
I now feel a lot smarter saying “smushing”, it being a scientific term used by world-class physicists. However, I’m more interested in the stick-bomb bit. This is explained best by Popular Mechanics in their report (stemming from the same scientific study by Hunter et al) on Why the Humble Bird Nest Is an Engineering Marvel.
As a fun project to while away the time indoors, build your own stick bombs using popsicle or jumbo sticks such as those available here.
The stick bomb illustrated in this video by Brain Coach Don offers a great deal of excitement, but I do not recommend it for building bird nests—ha ha. The difference is them making ones that are disordered and thus nonexplosive.
*(Mechanics of randomly packed filaments—The “bird nest” as meta-material, Journal of Applied Physics 127, 050902 (2020))