Because former Harvard University President Lawrence Summers was summarily defenestrated from his prestigious ivy-draped office (for presuming to observe that some sectors of the population-in Cambridge, Mass., a clear political, if possibly not demographic, majority-do better in graphics than numbers), I'll avoid the right-brain and left-brain question, and the underlying statistics in this column and go directly to the basic principle of consumer behavior and the charts which illustrate it.
The principle has been called the tipping point and it refers to the repeated empiric observation that, if and when 20 percent of the population make a consumer choices of goods or services, the remaining 80 percent mostly soon follow. It has worked in the past for such new goods as automobiles, refrigerators, and T.V. receivers, and most famously for services, showing up in such patterns as urban middle-class flight from court-ordered underclass school enrollment mixing, commonly labeled "white flight", although, as both Kansas City and Detroit statistics illustrated, middle-class black flight was numerically proportionate to middle-class white flight from newly-disrupted classrooms.
The chart here is the s-curve, which wasn't invented by economist Harry Dent but was publicized by him in his 1999 book, "The Roaring 2000s".
It has three phases: a slow "Innovation" stage where brave new consumers try it, a rapidly accelerating Growth phase, where most potential customers buy in; and a final declining-growth maturity phase, in which all of the late and slow who will ever try it finally join in. When you examine the curve you'll see that, if and when it gets to the 20 percent level of market penetration, almost all of the remaining 80 percent will usually soon follow, which explains why it's also known as the Pareto Principle or the 80/20 rule.
I use the qualifier "usually" because there have been exceptions. In education, for example, one took place in the years before and while I was a public school student, typically in 30-student classes with better-than-now test scores, and no college entrants in need of remedial instruction, when the non-public parochial school alternative was increasing its market share; it topped out at about 15 percent or so of total potential enrollment, the age 5-17 cohort. The other took place in the years after I was a public school student, when, I can recall reading, the American public education system was widely described as "the envy of the Western world"; when public education was perceived as so good that there was no need to pay even the typically modest tuition fee for the alternative, and so the market penetration of the non-public alternative shrank. In both cases, the s-curve didn't play out to full completion.
Back then, public education was so proud of its market-share ascendancy that state education departments would proudly report, when asked, what the percentage of non-public alternative was: three or four percent, they'd say. More recently, when you ask that question, you get a "we don't know" response. I suspect they know but, as with recent queries on school size in square feet and official capacity, choose to plead ignorance rather than reveal stats which might be, in their view, misused by such as your present scribe.
Recently, I've gone to an alternate source for the missing stat: the size of the age 5-17 cohort, which, compared with same-year public enrollment (note: it requires math proficiency to do the long division without a calculator) and here's what the Census Bureau has for Vermont.
The last official age 5-17 head count was executed in 2000, and will be again this year, but the web site shows estimates and projections for 2005 (112K) and 2015 (107K) from which one can derive an average (math proficiency again required) of 109.5K for the current year the Vermont SED website reports the present enrollment at 91,239. In a Grade 3 exercise (see the Kwiznet web page) you can see that, to obtain the public-enrollment percentage, the divisor is 109.5K, the dividend is 91K, and the quotient is 83K. Next, Grade 1 subtraction is required. Since the minuend is 100 and the subtrahend is 83, the remainder is 17. In modern basic English, two-syllable words max, the percent of age 5-17 students in non-public schooling is 17 (oops, a three-syllable number, there, twice).
Finally, compare 17 to the 20 which is the 80/20 tipping point number. It's close. Is non-public enrollment about to embark on the steep part of the Harry Dent s-curve? Is the Pareto Principle pending? As Vulpes Novus said, "Nos Renuntimus. Vos decernite."
Former Vermonter Martin Harris lives in Tennessee.