— Leland Teschler, Editor

Investigations revealed that these and other public works were often designed and constructed by individuals who had no real qualifications to do so.

Public outcry eventually persuaded individual states that engineers who practiced within their borders should pass an exam as part of a formal registration procedure. It often took a catastrophe to convince state legislators of the need for this measure. Texas, for example, didn't force its engineers to register until 1938. The catalyst was the explosion of a natural gas-fired boiler, which leveled a school in New London, Tex. The blast killed approximately 300 students and teachers and even today is considered the worst tragedy involving schoolchildren in American history.

The evidence is that engineering registration has had the desired effect. The U.S. saw on average more than one boiler explosion daily in the late 1800s. Now such calamities are rare. When they do happen, they are more likely caused by operators who defeat built-in safety features than by a fundamental defect in the design.

Contrast the track record of engineering registration with that of another profession: teaching. In the late 1800s, states also began to mandate that their teachers pass a locally run test to get a teaching certificate. But after 1900, education took a wrong turn. Increasingly teachers earned certification by taking courses in teaching methods rather than by demonstrating competence on the subject matter they were teaching.

One problem: Instructors knowledgeable in teaching methods can still be ineffective if they don't know their subject. And unlike the immutable laws of math and Newtonian physics, teaching methods remain open to debate. Educators still don't agree on how to teach, how to test, and on how to decide whether or not a teaching method is effective. Little wonder, then, that over the years teachers have dispensed such screwball advice as admonishing parents not to read to their children, arguing against the use of phonetics to sound out words, and promoting new math concepts that have become a source of ridicule.

Unlike what happened in engineering, professional certification of teachers didn't arise out of public outrage. It was seen more as a way to bring professionalism to teaching. Certification may well have done that, but formal credentials and expertise in teaching methods don't necessarily make students perform better. That is one conclusion of a study by the Public Policy Institute of California which found that teacher certification had only a minimal impact on student performance. Other studies have made similiar judgements. . All in all, you probably wouldn't want to trust a bridge designed by an engineer who hadn't passed the P.E. exam. But parents needn't worry if their kids are being taught by teachers who aren't certified.