A few K-12 education reforms that seem like they would work:
1. Start foreign language instruction much earlier. The norm should be 3rd grade, not 9th grade. Younger students inherently have more of a capacity to learn foreign languages.
2. Include a period of immersion of at least a month in a student's foreign language at least three times from third grade through high school graduation. Immersion is profoundly more effective than a single less than an hour class in a classroom in an otherwise English language context.
3. Strong preference should be given to native speakers and people who gained fluency by prolonged immersion at a relatively young age in teaching foreign languages. Formal teaching credentials are much less relevant in this field.
4. Be ruthless in always assigning children to math and foreign language classes by proven ability level even if this is inconvenient to administer. These are classes were a student taught something he or she has already learned is wasting precious time when he or she is most able to learn it, and students in over their head are going to see substantially reduced benefit. Probably a third or more of students in any given grade should be taking a math class at something other than their grade level.
5. Most large school districts, due to a need to make efficient use of transportation resources, run on two shifts, an earlier one for middle school and high school students and a later one for elementary school students. This should be reversed. Elementary school students tend to be more often at their peak in the morning. Tween and teens tend to naturally shift towards becoming night owls.
6. The standard 180 school days in a year is too short, and the average school day is too short. Another twenty week days per year and another hour a day would be a good start. Schools that consistently see higher than average student academic growth have students spend more hours per year in school, the long ago agricultural considerations for summer harvest time no longer apply, and if this means buying air conditioners for summer school sessions, so be it. It might make sense to used additional school days during the summer for programs that benefit from large blocks of time for instruction like foreign language immersion (in part, so students with parents who aren't married to each other in separate cities can do their block time in one parent's city, and the rest of their year in another). Some of the extra time can from by including extracurricular activities as a mandatory, but ungraded, element of every kid's day. Longer days and more school days also better respects the reality that a large share of students come from families where both parents have full or nearly full time jobs.
7. The concept of "physical education" should go. School children should get physical activity in the day, but the point should be the current benefit that flows from being physically active, not the knowledge that students learn from the activity. Also, almost all "physical education" classes are taught year after year as survey courses. There may be a place for a "survey course" format for small elementary schools where kids haven't been exposed to different possibilities and the school can't feasably offer multiple choices with its staff limitations, but this doesn't make sense in middle school and high school. Again, this is unnecessary and counterproduct when it comes to the real goal of providing physical activity. Few parts the school curriculum are better suited to offering students choices - let them take a yoga or dance class, or join an intramural or intermural sports team, or join a running group, none of which should figure into a student's GPA, instead of plain old "physical education." To the extent that there is an "education" component, it should focus on establishing specific life skills like learning to swim, learning to ski, and learning to ride a bike.
8. Preschool and full day kindergarten should be publicly funds and staffed with teachers paid what experienced high school teachers are paid. Studies have established that this part of educatioon has more impact than any other and that these teachers are currently the least bright. Also, full time schooling has been demonstrated to be highly effective at increasing family income and reducing child abuse and neglect.
9. More frequently advance academically high performing kids to a higher grade level and more frequently hold academically low performing kids back a grade level. Curriculums are designed to provide maximum benefit to kids who are a little about grade level. The closer kids are to that target in the majority of their classes in school, the better they'll learn. If enough kids finish twelve years of K-12 level work a year or two early, add a special college level program for them.
10. Decrease emphasis in teacher hiring on classroom education classes in training teachers, and increase emphasis on recruiting the teachers with personalities that are good fit for teaching and who are as smart as possible. The evidence that additional instruction improves teaching quality is quite weak.
11. Provide quick and honorable outs for teachers who learn in the first few years that teaching is not for them, and for teachers who start to burn out. Teachers who aren't thriving often want to get out and make room for better qualified teachers, but find it hard to find an acceptable way of negotiating that switch. Pension systems structured to create strong economic incentives to stay in the system for a certain number of years, no more and no less, discouarge that. There is also undue emphasis in teacher compensation on degrees earned and continuing education classes taken.
12. Students should receive more instruction at a fairly high level of rigor on negotiating the health care system and mental health care system from a patient's perspective (and self-care when possible), on basic accounting concepts and tax law compliance, and on interacting with the legal system (e.g. as a criminal defendant, if sued, if injured, as a tenant) as part of the high school curriculum. Almost everyone has to deal with these things in life, and these things are more demanding of academically teachable knowledge than almost anything else a typical person does in life. These are at least as important as sex education, don't use drugs propaganda, driver's education and civics that are all part of the curriculum.
13. Adjust the A, B, C, D and F grading system, perhaps by adding a new grade "E" above "A" and discarding the "D". The level of work that qualifies for a "D" is so bad that it is as if a student had never taken the class or worse, that kind of performance is unacceptable and shouldn't be given credit at all. But, the current GPA system also errs by focusing too much on across the board competence at a solid but unexceptional level (i.e. on not making mistakes), rather than accepting that truly excellent above and beyond performance in one area should at least balance out mere average performance in some other area. The "A" grade should have a similar lower cutoff to what it does not, while an "E" grade should entail "A" grade quality work in normal assignments plus work well beyond the scope of the curriculum for the grade level being taught and major "extra credit" projects such as a quality science fair or history day project, "an honors thesis," or extra beyond grade level curriculum level work. The fact that someone can't do better than "B" grade work in social studies, shouldn't count against someone who is doing "E" grade work in creative writing.
14. Developed a systemic way of screening, tracking and addressing learning difficulties, mental health issues, and disciplinary problems. These issues frequently are apparent by late elementary school. Almost everybody who has serious disciplinary problems or learning difficulties that are a big problem in high school and lead people to drop out have had clear yellow and red flags apparent to anyone who is paying attention by the time that they were in fifth grade. The system needs a way to proactively address these issues, rather than seeing incidents as isolated, seeing individualized learning plans as a pro forma paperwork chore (the emphasis should be on having a plan for a particular kind of problem, not on the individualized nature of that plan), and to devote intensive resources that may need to go beyond the school itself to address them starting as soon as the issues are identified. The longer these situations go unaddressed, the worse they will become. Letting things slide while given a student an opportunity to try to turn things around by himself or herself possibly with family help until they can't be ignored is not the right approach. Issues not to be addressed immediately when they start to appear because the older the student gets and the longer the problem persists without being addressed in a non-punitive constructive way that will help the student in the long run, the more likely it is to become harder to address.
15. Recognize that some degree of very personal intervention in habits and behavior, rather than just knowledge transfer, may be necessary to facilitate student learning growth and devise ways to do this that do so without inappropriately imposing religious or ethnic biases. This isn't an easy task, but seems to be a common thread in those schools that consistently show exceptional student growth.
16. Increase the weight given to growth measures in evaluating teachers and schools and decrease the weight given to absolute performance measures.
17. For choice options to work best, information about school performance needs to be conveyed to choosing parents on specific programs that students will be involved in, not obscured in a blend of different programs that happen to be co-located.
18. High schools should be evaluated based on post-graduate employment results as well as graduation rates, college matriculation rates, college graduates produced, and remedial instruction for students who go to college. The system should invest enough to allow high schools to have career searching assistance and college advising assistance that help them to maximize their performance on these measures, should track these outcomes, and should publicize the results.
19. At some point in middle school or high school, students who are unlikely to graduate from college should be identified and provided with multiple curricular choices that permit them to decide what they and their parents think will provide the maximum benefit to the student from the student's remaining years of taxpayer funded education. The current watered down college preparatory curriculum for these students undermines interest in school because it seems irrelevant and wastes the time of teachers and students alike.
20. Increase the mandatory school attendance age to eighteen for kids who have not graduated from high school. This policy increases graduate rates, reduces juvenile crime, and surprisingly, also doesn't reduce outcomes for kids who wouldn't have dropped out anyway.