Wednesday, April 27, 2011

Normal Accident Theory of Education, continued

Earlier, I started my Normal Accident Theory of Education. Here are a few key ideas necessary to advance the idea that education is rife with normal accidents or normal failures.

A brief but good overview of some of the definitions of key terms that make up Perrow's theory about Normal Accidents, by Professor Piccard of Ohio University.

High-Risk Systems

This term encompasses risks "for the operators, passengers, innocent bystanders, and for future generations." He applies it to "enterprises [that] have catastrophic potential, the ability to take the lives of hundreds of people in one blow, or to shorten or cripple the lives of thousands or millions more." This means that although he does include chemical plant and refinery accidents, he is explicitly excluding from his focus the primary harmful impacts of fossil-fuel burning (greenhouse gases and toxic combustion products released into the atmosphere), since those effects are diffuse and happen by design, not as an accident. Education and schools are a bit different. Their accidents are not deadly, but they do have lasting impact. Today especially, we look upon school processes and their outcomes as high-stakes. The consequences of failure, then, are serious, though not deadly.

Normal Accidents

Perrow uses this term in part as a synonym for "inevitable accidents." This categorization is based on a combination of features of such systems: interactive complexity and tight coupling. Normal accidents in a particular system may be common or rare, but the system's characteristics make it inherently vulnerable to such accidents, hence their description as "normal."
Education accidents (or failures) are common, though lower intensity than the fatalities that would be associated with a nuclear meltdown or a plane crash.

Discrete Failures

A single, specific, isolated failure is referred to as a "discrete" failure.
A student's failure of one course, or one standardized test, would be a discrete failure. So, where a nuclear plant might have a discrete failure occasionally, the education system produces its smaller discrete failures routinely.

Redundant Sub-systems

Redundant sub-systems provide a backup, an alternate way to control a process or accomplish a task, that will work in the event that the primary method fails. This avoids the "single-point" failure modes.

Interactive Complexity

A system in which two or more discrete failures can interact in unexpected ways is described as "interactively complex." In many cases, these unexpected interactions can affect supposedly redundant sub-systems. A sufficiently complex system can be expected to have many such unanticipated failure mode interactions, making it vulnerable to normal accidents. A student's failure to 'get an education' would be an interactively complex failure. A student must systematically fail courses, annual tests, etc., though these discrete failures may not necessarily amount to not getting an education. It is difficult to determine 'getting an education,' and we have increasingly defined that as passing all the classes and annual tests (or at least the last of these tests, 10th grade in WA state).

Tight Coupling

The sub-components of a tightly coupled system have prompt and major impacts on each other. If what happens in one part has little impact on another part, or if everything happens slowly (in particular, slowly on the scale of human thinking times), the system is not described as "tightly coupled." Tight coupling also raises the odds that operator intervention will make things worse, since the true nature of the problem may well not be understood correctly. The education system is loosely coupled, which means discrete failures here and there can be overcome. Persistence of discrete failure, however, which is, definitionally, evidence of interactive failure, can occur...with everyone's knowledge (so these failures are not incomprehensible--see below). One point of concern here. Perrow argues for decentralization of loosely coupled systems in order to allow flexible decision-making in the performance of the system. School reform portends increased centralization, though. This will increase the likelihood of normal accidents.


A normal accident typically involves interactions that are "not only unexpected, but are incomprehensible for some critical period of time." The people involved just don't figure out quickly enough what is really going wrong. A normal accident occurs in a complex system, one that has so many parts that it is likely that something is wrong with more than one of them at any given time. A well-designed complex system will include redundancy, so that each fault by itself does not prevent proper operation. However, unexpected interactions, especially with tight coupling, may lead to system failure. System operators must make decisions, even with ambiguous information. The process of making a tentative choice also creates a mental model of the situation. When following through on the initial choice, the visible results are compared to those expected on the basis of that initial mental model. Provided that the first few steps' results are consistent, the fact that the mental model was tentative is likely to be forgotten, even if later results contradict it. They become "mysterious" or "incomprehensible" rather than functioning as clues to the falsity of the earlier tentative choice. This is simply the way the human mind works, and systems designed with contrary expectations of their operators are especially vulnerable to system accidents.

Operator Error

It is indeed the case that people sometimes do really stupid things, but when most of the accidents in a particular type of system (airplane, chemical plant, etc.) are blamed on the operator, that is a symptom that the operators may be confronted with an impossible task, that there is a system design problem. In a typical normal accident, the operator's actions may contribute to the problem, or even initiate the sequence of events, but the characteristics of tight coupling and interactive complexity also make their contributions. This brings us to the question--what is 'the education system' and who are the operators? If the system is the parents, home, community and school, then the operator is the individual student. If the system is just the schools, then the operators are the teachers and other school personnel. If we call the schools the system, we in effect leave 'incomprehensible' the functioning of the other parts of the student's educational life, and leave the student as something of a cipher. an entity being acted upon rather than an principal-operator of an educational system created--by his/her parents AND the schools--to make an education available to him/her.

For want of a nail ...

The old parable about the kingdom lost because of a thrown horseshoe has its parallel in many normal accidents: the initiating event is often, taken by itself, seemingly quite trivial. Because of the system's complexity and tight coupling, however, events cascade out of control to create a catastrophic outcome. So, a cascade can come from a string of bad or inattentive teachers. Or, a cascade can come from a school and teachers monitoring and intervening, but other parts of the whole system (parents, student, etc.) not responding. I'm sure the former happens. I see several cases of the latter every year. Most common form--we identify a student who needs an intervention in math or reading, and suggest a one-quarter class for this, and the parent opts to keep their student in band or art. Parents' choice; school will be held responsible.


Organizational issues routinely confront the analyst of normal accidents. Because the interactions among subsystems are not predictable, the operators must be able to take prompt and independent action. Because of the tight coupling, in which operators of one part of the system influence the tasks confronting operators of other parts of the system, centralized control is required. These two conflicting requirements cannot be readily resolved, and the organizational attributes that work well for one side are likely to be dysfunctional for the other.
Schools and school personnel are increasingly bound, not independent, in their actions. There are school districts that tell teachers exactly what they'll be teaching on a given day. And, of course, as soon as the stakes are raised on the standardized tests, we incentivize teachers to focus more on the test, and, for some, to even cheat.
Okay, more later.

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