In the interest of working parents (the two-parent-job-holding family having become ever more common during this period), and in the interest of social stability and the orderly management of an increasingly rootless urban population, the schools have developed into immense teen-sitting organizations, their functions having less and less to do with imparting to the young those things that society thinks they must learn.  In this situation the content of education deteriorated as its duration lengthened.  The knowledge imparted I the course of an elementary education was more or less expanded to fill the prevalent twelve-year educational sojourn, and in many cases school systems have difficulty in instilling in twelve years the basic skills of literacy and numbers that, several generations ago, occupied eight.  This in turn gave a greater impetus to employers to demand of job applicants a high school diploma, as a guarantee--not always valid--of getting workers who can read (304).