I did a bit of searching and found an extensive study on the subject by the National Center for Time and Learning:
The study tracked 650 schools (both charter and public/district) that offered an expanded school day or year (on average these schools offered 25% more school time than the national average of 178 days/1100hrs) and found a statistically significant correlation between an expanded school time and student performance. The full report, including detailed results can be found here:
My daughter (she's a 7th grader in Millstone) also found a news article about Obama proposing a longer school year. What's most interesting about the article is the table that lists the school years of other countries.
My daughter and I are now independently researching states who have mandated a longer school year. So far, she's found Kansas and Ohio. Our goal is to look into whether these states have standardized tests and whether test scores show improvement after they have moved to the longer school year. This might take a bit longer. We'll let you know what we find.
An expanded school year may mean an increase in teacher salaries (the above report states that, on average, teacher salaries rose 14%; but the report also mentions that the proportion of schools in the study that were in economically depressed areas were higher than the national average. To me, this means that teacher pay in those areas were also depressed - so the 14% pay increases seen in these schools may not reflect the increase a suburban school district such as ours would face). But, again, our BOE just gave our teachers a 6% raise for really no reason I can discern other than a feeling by the union that teachers 'deserved it after not getting any increase the previous year' (never mind that inflation was near zero and there were no measured student performance improvements in the school district). So if we decided to move towards an expanded school year, there should be significant wiggle room in salary negotiations.
On a related front, the Millstone Examiner published what I thought was an interesting letter by a teacher of 46 years. The author's main thrust was that teachers should not solely be graded on the results of standardized tests as Christie seems to propose. I actually agree with this teacher! A better empirical way to assess a teacher's effectiveness is to measure the *progress* his students make relative to their academic history. For instance, student A takes a test both at the beginning and end of 7th grade and improves his math score by 10%. But in 5th and 6th grade math, his score improved 20% each year. This is an indication that the 7th grade teacher is not teaching this student as well as expected. If the other students in his class also show reduced improvements, the lack of effectiveness on the part of the teacher is confirmed. This method of assessing teacher performance is beginning to be used in some schools across the country.
The author of the Examiner article also makes the point that fostering a 'culture of learning' is just as important, if not more so, than the teacher: if kids are around parents who don't place much importance on academics or if kids hang out with other kids who don't value education, then they themselves will value education less. The author also found and admits that it's definitely true that K-12 schools don't adequately prepare kids for college: he found that almost 2/3 of the students who attend community college need to take remedial courses to bring them up to a college level! If true, that's pathetic. Parents wake up! You're basically paying for your child's education twice: once through property taxes into the ineffective K-12 system, and then again in the form of an extra year or so of college tuition on remedial courses!