"Spare no expense to make everything as economical as possible." -- Samuel Goldwyn =============================== "Michael Hodges" wrote (about evidence relating class size to student achievement): >Since I posted the original subject question of 'where is the >evidence', I am surprised that despite the many responses no one has >provided said evidence. Michael: There have been literally hundreds of studies that have failed to find any relationship between class size and student achievement since the famous Coleman Report failed to do so -- to the surprise of everybody, including Dr. Coleman -- back in 1966. (References below) But this result actually is to be expected. You and Jim as regulars of sci.econ should see the reason why. Expenditures on teachers' salaries and other educational inputs are substitutes for each other -- what you spend on one you can't spend on the other. So the real issue isn't whether smaller classes are better, but what's the most effective mix of spending. Competent school administrators will allocate their spending between teachers and other inputs until the marginal return from both is the same. That is the most effective mix of spending. From that position, if you conduct a study to see whether spending on teachers is more productive than spending on other inputs, the result will be that it's not, because it isn't. Any study that comes to a general conclusion that students would be better off if schools spent more on lowering class sizes and less on other things would indicate that those running the schools until now somehow have been too stupid to realize how to spend their money most effectively. If school budgets are being spent effectively, additional money spent on reducing class size isn't going to provide any obviously greater benefit than additional spending on other things. You've also got to add in the real world complication that different school districts, schools and students are in very different situations and are best served by very *different* mixes of spending. Some students surely would benefit from more personal attention and smaller classes. But some students are best served by larger classes that invest more money in other educational resources. Put these considerations together, and the surprising thing would be to have studies indicating that generally reducing class sizes *would* be an obviously beneficial strategy. Thus the perplexing result of many, many studies that most teachers have a hard time believing is explained. Parents and teachers almost always think in terms of smaller classes being good *other things being equal* -- overlooking the fact that spending to reduce class size *must* carry a cost somewhere else by reducing the amount the school system spends, or could spend, on other educational resources. If the educational benefits lost with the foregone spending outweigh those gained from lower class size, you lose. Parents and teachers also overlook that it is *hugely expensive* in terms of other educational resources to reduce class size. First you have to hire more teachers, a cost that increases at an accelerating rate the lower you go. To reduce classes from 30 to 20 students you need 50% more teachers, to reduce them from 30 to 15 you need 100% more. Then you need to add an equal number of additional classrooms, a big capital expense. You've also got to *raise teachers' salaries*. If you try to significantly expand staff without raising pay levels to attract a larger number of qualified candidates, the quality of the teaching staff will decline. The result will offset any benefit you expect to get from smaller class sizes. And you'll have more overhead -- training for the new teachers, additional management for expanded payroll and physical plant, more classroom maintenance, etc. Finally, you must realize that while teachers' salaries are *consumed*, alternative investments in educational resources can *accumulate*. Say that investments in libraries, computers, laboratory equipment, building improvements, and so on, have an average useful life of five years. Then the cost of each extra teacher is *five times* that teacher's annual total compensation in foregone investments in other educational resources -- plus a substantial amount more for all the 'extra' costs described above. Is a class size of 15 or 30 is better? Almost any parent or teacher will answer 15, automatically. But where I am the average teacher costs the public school system $50,000 annually in salary and benefits. So the *real* question is: Is a student better off in a class of 15, or in a class of 30 with well over $250,000 of extra educational resources *per classroom*? (Or perhaps in a class of 30 with the $250,000+ spent on some other mix, such as a much-higher paid and better-qualified teacher and extra resources, or a teacher's aide and extra resources, etc.) The answer isn't so obvious -- it depends on the situation. When students have behavioral issues or needs that require individual attention, smaller classes may be best. That's not just for troubled students, but especially for young, early-grade students who are learning the behavior they will practice the rest of their educational lives. But if students are capable, self-motivated and intent on learning, you may well want *larger* class sizes to attain economies of scale and be able to spend more on resources they can utilize. This is no secret -- when top high school graduates go off to top universities they often finds themselves in freshman lecture classes with 100 or more students Why are high school classes with 30+ students bad, but classes at top universities with 100+ students good? It's the not the class size, it's the students. Sometimes the difference between "rich" and "poor" schools with the same per-student budgets is just class size. NYC just gave its premier academic high school, Stuyvesant, a new building designed to hold over 3,000 students in big classes. The economies of scale let it build the school with modern labs, an Olympic swimming pool, a theater, and everything else a school could possibly want. But only the city's very best students are "cream skimmed" into Stuyvesant, by competitive examination. Would the talented students at Stuyvesant be better off if they were shunted off to several smaller schools with smaller classes, while being deprived of all the resources available to them now? No. Meanwhile, the rest of the troubled NYC school system is following the "small school/small class" trend, and spending all of $40 per year, per student on books -- about 1.5 books each. I've seen classes using textbooks 20 years old. Would the kids in the smaller, poorer schools and classes be better off in larger settings with more resources? Maybe, maybe not. It depends. But it's simply naive to ignore the tradeoffs involved and assume that smaller class size always must be better. BTW, the quadrupling of administrative cost per student that's occurred in the US public schools over the last 30-odd years has had the same cost in resources as adding new teachers, without the benefit of putting teachers in the classroom. Multiply each non-teaching employee's salary several times over, and that's what he/she costs the system in educational resources. If that person really isn't necessary -- and the public schools used to have a *lot* fewer non-teaching positions -- that cost is a deadweight loss, hundreds of thousands of dollars per person in assets lost to the schools. Recently, there have been a few studies of programs that have allocated new, dedicated funding to reduce class size, which claim to find educational benefits resulting. The Tennessee study mentioned in this thread is an example. But none of these studies try to determine whether the same money could have been spent *more* effectively in other ways, so they prove nothing -- they are experiments without controls. And follow-up studies by outside researchers who have sought to determine the cost effectiveness of these 'dedicated funds' programs have near universally found that they are *not* cost effective -- spending the same extra money in other ways would be expected to produce the same or greater benefits. For anyone who's interested in hard research -- rather than baseless usenet opinions -- on the returns from spending to reduce class size, and from spending on other educational inputs, a good survey of current research is _Assessing Educational Practices_, edited by William E. Becker and William J. Baumol, MIT Press. Some brief excerpts on the class-size issue: "Teachers and parents overwhelmingly favor small classes, but their value has been devilishly hard to prove in spite of volumimous research. "Three recent studies (Card & Kreuger, Ferguson, and Folger & Brenda) finally provide some small support for the idea. However, the first two studies do not examine the question of cost effectiveness. Folger & Brenda found that reducing class size from 25 to 17 produced modest gains that appeared only in kindergarten and first grade. They conclude that reducing class size is not cost effective... The case for general reduction in class size is weak. "Stevenson & Stigler suggest a better way to use additional funds than reducing class size. After examining international practices, and citing evidence that academic improvement can be achieved more effectively through improving teacher training and increasing academic rigor in the classroom, they propose *increasing* class size somewhat and investing the savings in training and giving teachers' more time out of the classroom to interact with other teachers. "This implies reorganizing the way schools assign duties to teachers. "Whatever the merits of the Stevenson-Stigler approach, legislators and school boards need to find better ways to use additional money as it becomes available than simply reducing the number of students in each classroom." That's right folks, top-down mandates of across-the-board reductions of class size are a *bad* idea. If anyone's interested in reading the studies mentioned in this extract, I'll provide journal citations by e-mail on request. Regards, oldnasty@mindspring.com (Grinch)