Other charter schools are backed by large private foundations apparently devoted to dismantling public school systems . It is significant that very few charter schools have teachers unions, salaries are generally lower than in public schools, and teachers are often less qualified than those in public schools.
Many charter schools look better than they really are because they use a variety of techniques to filter out weak students, even tho they purport to be open to all . They often do lobbying and mount substantial advertising campaigns. It is not surprising that commercializing schools has attracted a number of unsavory operators to exploit the situation . In general, it is a bad idea for schools to be run with the idea of making money. Unfortunately, that is the case for many, perhaps most, charter schools.Testing
The idea of using standardized tests to evaluate students, teachers, teaching methods, and schools seems very reasonable. But, in practice, there are serious problems.
A basic issue is that, when student test performance is the basis for evaluating, not only students, but also teachers, administrators, and schools, the principal objective of the system becomes increasing grades on standardized tests. Classroom time is dedicated to such matters as learning the answers to the kinds of questions expected on the exams in each area, and strategies for guessing the answers to multiple choice questions. Subjects not covered by the exams are given short shrift, and in-depth classroom discussions are regarded as a waste of time.
Cheating has always been a serious problem in our schools, but, in the past, the cheaters were the students; teachers and administrators tried to minimize it, tho they often did this poorly. Now, with high grades being important for teachers and administrators, as well as for students, it would be very surprising if cheating were not much more widespread. Apart from deliberate cheating by teachers or administrators, exams may be proctored carelessly. Grading process errors are yet another problem.
Another mode of cheating available to administrators of charter schools is to increase the average test scores of their schools by encouraging the weakest students to be no-shows on exam day, or simply to drop out of school. Reclassifying inept students as mentally retarded is yet another technique for making a school look better.
There is no way that short-answer or multiple-choice questions can properly test a student's writing ability. In general, questions that about half the students can answer correctly are the best, because they do the best job of spreading out student grades. This leads exam creators to avoid both very easy and very difficult questions. One result is that they do not identify the best students.
Exams can provide potentially valuable information about a student's weaknesses that need attention, but the time lag between taking a standardized exam and getting the results is generally so great as to make the information much less useful.What needs to be done?
Rather than allowing our public school systems to deteriorate, every effort should be made to strengthen them. Instead of whittling away at school budgets, they should be increased. Teachers, including teachers of pre-school children, should be treated with more respect and paid more. This would benefit all Americans as a better educated population would return rich dividends, and reduce many nagging societal problems.
There are already many excellent public schools in the US that specialize in various areas, such as science, technology, and the arts. No reason not to have more such schools. Perhaps some might be designed to accommodate children handicapped in various ways (altho it might be even better to make it easier for such children to attend regular schools.) Some applications of modern technology (e.g., the internet) can be very useful in schools, but care must be taken to avoid serious pitfalls .
Market-based reform in the field of education is not an effective approach . The problems faced by public schools cannot all be solved by schools themselves. As pointed out above, impoverished people inevitably produce many children likely to cause all kinds of problems in schools. Pre-school programs for low-income families, along the lines of head start, which include introductions to reading and arithmetic as well as educating parents about nutrition and other health-related matters, should be expanded and improved. Programs for providing food to poor people should be expanded--not cut, as is being done now.
It is disgraceful that a country as well endowed as the USA should have many tens of millions of poor people living under Dickensonian conditions, and even more disgraceful that their number has been growing in recent decades. Improving our schools is just one more motivation for attacking the problem of gross inequality.
Addendum 11/26/13: I am appending an additional reference  that was just brought to my attention. This is a lengthy essay, with many interesting observations and ideas; I agree with most, and disagree with a few.References
 David Sirota, "The Connection Between Poverty and Education", Truthdig, Nov 8, 2013
 Suevon Lee, "By the Numbers: The U.S.'s Growing For-Profit Detention Industry" ProPublica, June 20, 2012
 Jose L. Gomez del Prado, "The Privatization of War: Mercenaries, Private Military and Security Companies", Global Research, October 11, 2013