Randomization provides an essential hedge against time-related lurking variables, such as increasing temperature and humidity. It made all the difference for me succeeding with my first designed experiment on a high-pressure reactor placed outdoors for safety reasons.
Back then I made use of several methods for randomization:
- Flipping open a telephone directory and reading off the last four digits of listings
- Pulling out number from pieces of paper put in my hard hat (easiest approach)
- Using a table of random numbers.
All of these methods seem quaint with the ubiquity of random-number generators.* However, this past spring at the height of the pandemic quarantine, a software engineer Gary Briggs of Rand combatted boredom by bearing down on his company’s landmark 1955 compilation of “A Million Random Digits with 100,000 Normal Deviates”.**
“Rand legend has it that a submarine commander used the book to set unpredictable courses to dodge enemy ships.”
Wall Street Journal
As reported here by the Wall Street Journal (9/24/20), Briggs discovered “soul crushing” flaws.
No worries, though, Rand promises to remedy the mistakes in their online edition of the book — worth a look if only for the enlightening foreword.
* Design-Expert® software generates random run orders via code based on the Mersenne Twister. For a view of leading edge technology, see the report last week (9/21/20) by HPC Wire on IBM, CQC Enable Cloud-based Quantum Random Number Generation.
**For a few good laughs, see these Amazon customer reviews.