What's behind the decline of public schools.

• Author: Peltzman, Sam

The growth of teacher unions, loss of local control, the push for desegregation, and the decline of blue-collar jobs - all have contributed to the problem.

Imagine Taking a trip back through time to a classroom of a generation ago. Many things are different. Perhaps the most obvious is there are a large amount of students, about 40% more than a typical classroom of today. One can look around in vain for a teaching assistant or a lot of equipment. Instead of modern audio/visual gear, there may be a scratchy old record player in the corner, probably shared with a few other classes. There are far less books and art materials, and they are doled out more sparingly. There is an altogether forbidding austerity about it, compared to today's more intimate and friendly place. Austerity is the appropriate word. This classroom is getting by with about one-third the real dollar expenditures of those of the 1990S.

There is another fact that comes as a considerable embarrassment to the voyagers from this generation - this classroom seems to be turning out better-educated students. At least in terms of basic knowledge, of literacy and numeracy, the average high-school graduate apparently is no match for his or her counterpart of a generation ago. While it is possible to quibble with the details, the broad facts are beyond any serious dispute. Performance of students has declined noticeably.

The most widely cited statistic is the drop in SAT scores. While there is some dispute about whether these exaggerate or understate a little bit, they do convey the essential point: In today's crop of college freshmen, only one-third are doing better than the average freshman of a generation ago. In an important respect, this is old news. At least it can be said that, over the last 10 or 15 years, things have not gotten worse; in some respects, they have gotten better. Yet, on the whole, as a broad generalization, schools today are performing at roughly the level they were in 1980. The intriguing question is: What happened in the half-generation prior to 1980 to bring American schools to where essentially they are today?

During that period (approximately 1965-80), real expenditures per student doubled as teacher ratios declined by one-fourth. Meanwhile, student achievement deteriorated badly by every available measure. For an ordinary business to double its inputs, yet somehow manage to produce less is unthinkable, but that's what happened to American education in this roughly 15-year period leading up to 1980.

Why did this occur? Attempts of social scientists to uncover the source of this deterioration have been largely unsuccessful. The difficulty is that the decline was so sudden, sharp, and pervasive, it affected every region and socioeconomic group. Virtually nothing that distinguishes the 1960S and the 1970s from other decades can be ruled out as a cause. On the other hand, the suddenness rules out the operation or important contribution of any long-run trend that was well under way by 1960.

Rather than seeking a single answer to the question of what went,wrong, let us examine one aspect of the problem that often is neglected-the political context within which American schools operate. American elementary and secondary education overwhelmingly is a public enterprise. The public sector accounts for about nine out of...