“There is no rule without an exception.”
(Thomas Fuller, MD, Gnomologia, 1732)
“No rule is so general, which admits not some exception.”
(Robert Burton, The Anatomy of Melancholy, 1621)
“Rules are mostly made to be broken and are
too often for the lazy to hide behind.”(General Douglas MacArthur)
“A rule of thumb is a homespun recipe for
(Tom Parker, Rules of Thumb, A Life Manual, pg.vii)
making a guess. It’s an easy-to-remember
guide that falls somewhere between a
mathematical formula and a shot in the dark.”
“A rule of thumb works four out of five times
(including this one)”(Paul Devaney)
We’ve all heard the phrase about rules being made to be broken. And, sometimes, for all the right reasons and the appropriate situations, they probably should be. I think that’s kind of where the so-called “Rules of Thumb” come into play. That’s because we all use that rule each and every day, in fact, many times a day. These rules are simply mental tools to help us quickly appraise a situation or solve a problem. And, these appraisals or estimates of yours, and mine, cover just about every subject imaginable: money, relationships, cooking, health, travel, restaurants, home, etc. Essentially, a rule of thumb refers to an approximate method for doing something based on practical experience rather than theory. The earliest appearance of the phrase in print comes from a collection of sermons by Scottish preacher James Durham in 1685: “Many profest (professed) Christians are like foolish builders, who build by guess, and by rule of thumb (as we used to speak), and not by Square and Rule.” The usage of the phrase can be traced back to the 17th century and has been associated with various trades where quantities were measured by comparison to the width or length of the thumb. Hence, the thumb used as a “ruler” for measuring purposes — the rule of thumb!
Employing a rule of thumb prior to making a decision — whether a momentous one or something more mundane and insignificant — allows us to consider the potential outcome based on our own, personal background, common practice — and, what makes sense to us at the time. However, while every rule that’s ever been introduced has undoubtedly been broken, time and time again, I would venture that the one rule that has not been broken is the rule of thumb. And, while whatever judgement, selection or guesstimate that we eventually make in using the rule of thumb — whether it turns out to be the correct one in trying to solve our problem, or not — we’re still using the rule and therefore not breaking it at all. Or, as attorney Stephen Verbit offered: “Every rule of thumb has at least one exception, except this rule.”
Well, as far as rules go, we’d all probably agree that they’ve been established over the years for the basic welfare and safety of humans, as well as to avoid legal, medical or other, unintended consequences. Rules do keep things fair, and they allow you to know what to expect in most situations. Largely, obtaining for us a balanced level of safety, fairness, order and justice. Obviously, some rules have even been codified into laws, and breaking them can result in serious consequences. So, it just makes good sense to obey the many rules out there that over time have evolved — and been largely accepted; if followed, they would mostly keep us safe and protected. Let’s face it: life without rules could lead to danger and chaos.
But again, in the absence of any extremely consequential or dangerous situations that could potentially arise from a decision, the first thing that most of us turn to is a reasonably educated guess. And over the years, many of the same category of guestimates about a specific problem or question have occurred to a whole host of we humans. You and I have most likely used a particular rule of thumb ourselves, and perhaps thought it was original with us. However, it most likely existed out there already; many other folks have probably already cited it and used it, and we were simply the latest in a long line to give it a go.
Typically, here are some you may have come across:
- “You should keep at least one car length between your car and the car ahead of you for every ten miles per hour of speed.”
- “Never go to bed mad. To stay married, patch up your arguments before you go to bed.”
- “The more attractive and colorful the bird, the more likely that it is the male of the species.”
- “If your tank is on empty and you’re trying to make it to the next gas station, cut your speed to 35 miles per hour.”
- “The carpenter’s rule of thumb: measure twice, cut once.
You’ll recognize these as classic rules of thumb, known and employed by most of us at one time or another. There are certainly many more thumb rules out there, but one I’m sure you’ve heard of many times through the years is the 80/20 Principle. It goes something like this: “80% of the output or results will come from 20% of the input or action.”
It is also known as the Pareto Principle. And, that’s because way back in 1906, an Italian economist named Vilfredo Pareto, while strolling through his garden, came to a very interesting conclusion: he began to notice that every year, 20% of the pea plants in his garden produced approximately 80% of the peas. (Mark Manson, “The 80/20 Principle and How It Can Change Your Life.”)
Pareto went on to consider economic output on a larger scale, and so he began to find that when he investigated various industries, companies and even societies, that 80% of the production often came from the 20% most productive portion. (Manson). Over time, the 80/20 Principle has become firmly embedded in our culture. It has certainly had a strong impact in big business:
“The 80/20 Principle has historically been most popular in business management situations.
(Manson)
Businesses often found that roughly 20% of their customers brought in 80% of their sales. They found that about 20% of their sales reps closed 80% of the sales. They found that 20% of your costs led to 80% of their expenses. Microsoft and other tech companies have found that 20% of the bugs they found create 80% of the problems for their users.”
Here’s another 80/20 rule of thumb that I came across:
“As a manager, expect 80% of your work to be done
(Waldo Weyeris, engineer)
by 20% of your staff. Also, expect 90% of your headaches/problems to come from 10% of your staff.”
I’m thinking back to my college days when I spent several summers working in the Mennen Products plant in Morris Township, NJ. It was there I first heard a phrase that referenced the old 80/20. One of the line supervisors said to a colleague: “It’s the same 20% of the crew here who are always involved in 80% of the accidents.” Most production plants have message boards all around that proclaim: “_ days since the last workplace accident.” And, Mennen’s was no exception. It was a number to which management paid attention.
At some point, for my own edification, I took some time to look further into the subject of workplace accidents. It seems that literally 80 to 90% are caused by human error. Not only that, but the 20% group who cause most of the problems are a subset of error-makers who are what is called in the language of insurance companies: “accident repeaters.” Recidivists, really, who keep on reverting to careless behavior. These repeaters are those who log at least five recordable injuries in three years. A Canadian study found fatality rates and
workers’ comp costs for accident repeaters was ten times higher than for other workers.
Of course, in addition to the 80/20 there are a number of other rules of thumb that cite certain percentages:
- “1% of the users of a website activity create new content.”
- “Monthly rent must be equal to, or less than, 1% of the purchase price.”
- “When interest rates climb, every 1% increase in rate will decrease your buying power by 10%.”
- “The Rule of 72: You can tell how long it’s going to take for your money to double if you take the number 72 and divide it by the interest rate you hope to earn.”
- “60/40 Rule: For investments, you should have 60% of your portfolio in stocks and 40% in bonds.”
- “70/20/10 Rule: Individuals tend to learn 70% of their knowledge from challenging experiences and assignments, 20% from developmental relationships and 10% from coursework.
- “70/20/10 Rule: Divide after-tax income into three categories; 70% for living expenses, 20 % for savings, and 10% towards debt.”
So, I hope that I’ve provided you with an interesting look into rules of thumb. I know that I’ve uncovered quite a few new ones myself as I worked on this essay. In conclusion, I’d like to share with you several of my own personal rules of thumb. These have been floating around in my head for years and years, and I have to say that for the most part, these educated guestimates of mine have largely been on target.
So, here goes. Frank’s Rules of Thumb:
• When someone tells you who they are, believe them the first time. Obviously, I stole this from Maya Angelou. However, I’ve always felt fairly confident in my first impressions of people that I’ve met over the years. I also tend to pay close attention to a person’s actions. If they are ultimately not who they might pretend to be, after a while their behavior will give them away. Positive or negative, who they truly are will come to the surface. Of course, I have occasionally been wrong in some of my initial assessments, but rarely. So, this rule of thumb has had a pretty high percentage of correctness over time.
• Usually, the best relationships between couples are derived from the women being friends initially, and then their boyfriends/husbands becoming friendly over time. Unless a guy is a complete and utter a-hole, the men will ultimately not only get along, but may even develop a fine and lasting friendship themselves. But, if the women don’t see eye to eye and aren’t close and trusting of one another, then that couples relationship is dead in the water
• Take care of today, and tomorrow will take care of itself. Or, to put it another way: if you want something in your life to work out for the best in the future, then be positive right now and proceed as if it will come to pass. It still may not happen for you every time, but I can pretty much guarantee that it absolutely won’t go your way if you don’t at least picture it happening. I firmly believe that intent is an important factor in this particular rule of thumb of mine. I think intent is the element that provides a motive behind a person’s thoughts and actions. It shows (even to oneself) that you have a purpose and a firm resolve to make things happen. And remember, there’s nothing negative about being positive.
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Resonance 