The test of a high school's quality is its students' progress after graduation. H.D. Woodson High in Northeast Washington, like most high schools, produces graduates of a very wide range of abilities. As Peter Perl reported in this newspaper Saturday, some members of its class of 1980 are now doing well in highly competitive colleges. But some are unemployed and, you have to suspect, unemployable. As you read through the notes on these youngsters' lives, a year and a half out of high school, it is impossible not to reflect on the city's interest -and the nation's -in shifting the balance toward a greater probability of success for them.

The American high school is one of this country's most valuable and most cherished institutions. The secondary education system works. But it has been overloaded with responsibilities -some of them irrelevant, some of them contradictory.

Conversatins about the alleged collapse of the high school generally begin with exclamations about students' poor grasp of the basic subjects. The conversations will generally begin to get more lively, not to say violent, when you ask what precisely is meant by tha tfamiliar term "basic." Americans used to think that there was a self-evident answer, but that answer has disintegrated over the past generation. Some of your fellow citizens think that the list of basic subjects needs to include not only reading and writing, but instruction in health and what's vaguely called family living. Some think that it needs to include a thorough introduction to that new universal tool, the computer. Some see the high school as the best, and perhaps only, place to deliver important messages about social values.

A higher minimum standard of competence -an improvement that we have often supported in this space -probably means less attention to the disadvantaged and handicapped. A more rigorous curriculum means a more rigid one at the expense of the courses about film-making, drug abuse, ethnic groups, the environment and the rest. In the interst of persuading each student of the real opportunities open to him, schools in recent years have very often badly misled them about the degree of difficulty in actually getting tinto college and staying there or holding a job.

All of these choices are difficult, annd the country as a whole does not seem to have made up its mind on any of them. The consensus is now moving in favor of a more demanding academic program, with more precisely enforced standards. But it is moving slowly, reluctant to shed any of the other responsibilities that it has imposed.

The American high school, even with its present wildly diverse agenda, continues to be remarkably effective. To make it more effective. To make it more effective doesn't mean merely telling it to shape up and do its job better. It means, first of all, agreeing on the job to be done.