THRESHOLDS: FOR BABIES AND ADULTS.
Some psychologists have suggested that "the world of the newborn baby" is "a giant buzz". That the neonatal child is overwhelmed with sensations. Infant maturation after a few months is a process of constructing thresholds that screen or filter out all but extremals above the threshold levels grown in the nervous system, enabling the baby to develop regularity of behavior and learn to cope with its environment or articulately plea for help in coping.

This is comparable to the problems faced by

We know the extremals of the latter role: too little attention leads to losses or interferences with behavior; and too much attention can lead to paranoia.

Not to cry! The quality control engineer found a "middle" ground between these two extremes. It was tested in World War II in supplying both armed forces and domestic needs; and it has enriched our postwar society. And clever managers have discovered it how to adapt this "middle ground" to their business environment, with great success.

What is it? And "can I order a year's supply"?

That "middle ground" of the quality control engineer is an "averaging" (arithmetic mean) of the number of defectives in a random sample taken from the production line. (The word "mean" derives from a word denoting "middle".) The engineer uses this mean to calculate a statistical measure known as "variance" (variation about the mean), in order to obtain its square root: "standard deviation" as basic unit of the normal distribution curve. In particular, the engineer calculates 3 standard deviations above the mean, and 3 standard deviations below the mean. Why? Because theory shows that 99.38% of the entire distribution lies within plus or minus 3 standard deviations of the mean. That approximate 0.72% (72/100th part of 1%) outside the control lines represents the "bad" and "good" EXCEPTIONS or ANOMALIES of production.

The measure of +3 standard deviations from the mean becomes "the upper control line" of the normal distribution chart; the measure of -3 standard deviation from the mean becomes "the lower control line" of the normal distribution chart. (These are the thresholds for the engineer.)

Then, the engineer has a strategic policy: only investigate numbers of defectives above or below the control lines -- what is EXCEPTIONALLY or ANOMONALLY "bad" or "good". Investigating "anything else" may be "a waste of time".

A number of defectives above the upper control line could indicate that the production process "may be going out of control and too many defectives will be produced"; if below the lower control line, then something "good" may have happened to the production process (different raw material or different working of it or better workers) and should be taken advantage to improve the general quality.

Now, just as thresholds allow the baby to learn coping with her/his environment, so the control chart thresholds allow the engineer to cope with the production environment. It's called "engineering-by-exception": devote engineering skills and experience only to the exceptions above or below the control lines. There's energy and time and money for that, so it becomes a successful pursuit.

Managers learned from their engineers to adapt this procedure to the administrative environment in "management-by-exception": set up routines for dealing with the routine in routine ways, freeing the manager for the nonroutine. There's energy and time and money for that, so it becomes a successful pursuit.
Those thresholds of the baby mature into adulthood. They are, of course, limited to the senses and to what the semiotician (sign-studier) calls "indicator" and "signals" (indicators under physical and linguistic control) of "the natural environment". Educatiom and experience can contribute thresholds involving the iconic and symbolic environments. But at least two problems arise here: We can adapt the methodology of the engineer and the manager to develop security-by-exception -- so that we have the energy and time and money for dealing with "the good news is" and "the bad news is".

A file at this website, "Quality Control Graphing", tells you about the technique. If you have no one to help you in this, you can learn the needed statistical calculations in Schaum's Outline Series, Theory and Problems of Statistics, by Murray R. Spiegel, McGraw-Hill Publishing Co. -- $14.95 at Amazon.

And other files at this website will teach you how to construct "logical thresholds" -- "Securability Measuring Program", etc. -- information you will find nowhere else, since it's my own creation. If you can do better, be my guest.

Given these, we may be able to cope with "this new world of terrorism" by "arming" with security- by-exception or security-by-threshold.

Do we really need this? Zoologists have provided us with a comparison (in the natural environment) to the terrorism which so often crept up on us:

(If you examine the news and literature that emanated after each of these catastrophes, you see that all sorts of EXCEPTIONAL (ANOMONAL)events occurred at various sites and in various time intervals -- EXCEPTIONS (ANOMALIES) which should have been investigated at the time. And new precautions were put in place. Is their totem the Wampus Bird who flies backward so he can see where he's been?)

Folklore has claimed that a snake is able to hypnotize a mouse in order to capture and swallow it. But slow-motion photography by zoologists clearly shows that the snake achieves this by tiny movements whose detection is below the threshold of observability of the mouse -- until it is too late.

The mouse cannot be given a lower threshold (by any method presently known), but we can adopt lower thresholds that detect possibly "creeping terrorism" before it strikes.

And the "beauty of it" is that these thresholds are TUNABLE: if "control lines" are too high or too low, the new data of failures feedback for suitable modification those control lines. If the logical processing is inadequate, then, of itself, it requires feedback of that data t prepare more sensitive processing.

And these are rational procedures of known structure (not Government secrets), open to correction or improvement by any new ideas or new contributors or other advances in the state-of-the-art.

The Military Establishment has long practised mock warfare to prepare its Service men and women. You can emulate this. Elsewhere, I described how to form local networks for your edification and protection. The technology of 2000-2001 has provided means (a "card", available, say, from Radio Shack) for constructing a LAN (Local Area Network) for such a network. You can set up "opposing teams": one team of "creeping terrorists", and the other to use detection and analysis of EXCEPTIONS in daily events to try to thwart the other side. Information obtained from such try-outs can be used to tune your statistical and logical thresholds.

And you can establish a website to communicate and share learning with other networks.

The tools are there. Help-yourself-to-help-others-to-help-yourself!