The Time Factor: It's Not Just KIPP

In this post, I argue that it is important to understand why a few charters (like KIPP) perform better than others. An editorial in today's Washington Post points out that KIPP’s results suggest the achievement-improving potential of more school time for lower-income students – i.e., longer days and years.

Through longer days, mandatory Saturdays, and summer school, KIPP students spend about 60 percent more time in school than typical regular public school students. That's the equivalent of over 100 regular public school days of additional time. This is an astounding difference.

But it's not just KIPP.

Many (perhaps most) of the urban charter schools that get relentless national attention for their results have their students for much more time than regular public schools (which typically provide 6-6.5 hours a day).

For instance, the much-touted Harlem Success Academies, like KIPP, run almost 9 hours per day (about 40-50 percent more time). Achievement First schools (in New York and Connecticut) provide an 8.5 hour day and summer school. The BASIS charter schools in Arizona run almost 8 hours. The Aspire schools in California have a 7.5 hour day and 10 more days than regular publics in the state. The SEED charter schools use a boarding model that keeps the students 24 hours a day, 5 days a week.

So, how much of the higher performance of these widely-publicized charter schools is attributable to the simple fact that they have the kids for the equivalent of 40-100 additional days?

This is a difficult question to answer empirically. The KIPP report couldn’t measure the effect of school time because KIPP schools don’t vary much in their days and hours, and researchers cannot differentiate the time effects from the overall school effects. More school time is also often correlated with other variables, such as revenue (which is needed to keep schools open longer, and which these charters often receive from private donations), and it is tough to isolate these variables’ effects.

But both of the most recent charter lottery studies (here and here) find associations between school time and higher performance. These findings square with other evidence outside the charter realm, such as this clever Education Next article's use of snow days to estimate the effect of longer school years, and there are several analyses showing that student attendance (i.e., more time in school) improves performance (see this recently-published paper). There is also common sense: What school couldn’t do better with a few extra months?

Some charter advocates would no doubt argue that more school time is an inherent part of the “charter advantage," since so few regular public districts have established a longer day or year (and many are cutting them back for budgetary reasons). But this is more of a political than an empirical argument about “what works." It also ignores the fact that additional time has been successfully tried in urban districts, such as the longer days and years in the Chancellor’s District in New York City (also here) and the School Improvement Zone in Miami-Dade.

I’m not saying that charter school effects should be dismissed if they are largely explained by longer school days/years. Actually, I’m saying the opposite: If this is the case, then we should consider it among the more important findings that charter school research can produce.

Charters like KIPP are held up as models of what schools can achieve with students from low-income families. As examples, these schools provide much of the rationale for the continued expansion of charter schools, despite growing evidence that most charters don’t work any better than regular public schools and many have results that are worse. If this success largely boils down to an extra few months of school time, this should, in my view, change the substance of the charter debate immediately and permanently. We will have discovered "charterness."


It is always interesting to read about the "success" of charter schools. Thanks for this perspective. I have worked in the NYC public school system for over 25 years as a school secretary, the last 16 in special education, and I know the value of good teachers and sufficiently funded educational programs. I've seen the progress our teachers make with general and special needs students in a regular school year with less than adequate resources and I am always amazed. Let's face it--we don't have the money, resources, time and support that is lavished on charter schools If we did, we would leave charters in the dust and there would be no controversy. We also don't exclude students because of their language issues or special needs nor do we want to. It is very telling that many charter school staff are reaching out for representation from their local unions. I think we'll eventually come full circle and realize that public schools and unions are part of the fabric of our nation and we need to support not knock them.


What a thoughtful and even-handed piece. As a charter school founder, I'm sick and tired of the us-vs.-them mentality that pervades discussion of charter and district schools from all parties. We're all in the same field.

My experience tells me that the charter vehicle confers far more important advantages than more time - chiefly the ability to keep politics out of the classroom by shutting out the churning bureaucracy that defines our modern urban school districts. But that advantage is neutral; it can be used for good (compelling vision democratically enacted) or for evil (top-down, test prep teacher burnout machine).

Who knows - maybe you're right. It's a compelling argument.


What about the "creaming" factor? With their codes of conduct, volunteer demands, and the fact that many families simply don't know about them, charters simply start out with "better" students.

Longer days/years are not the answer, nor are they the reason charters seem to have better outcomes. Oh, and they don't have better outcomes.


It seems clear that you believe longer days/years have an effect:

There is also common sense: What school couldn’t do better with a few extra months?. A few extra months, by the way, is all of them!

And your post is full of comparisons to traditional public schools, making your "comparing charters with other charters" statement erroneous at best.

Why not be honest about charters: they are no better than traditional public schools, they (and their funders/pushers/CEO's) have discovered nothing about a new pedagogy, and they are the prime force behind the re-segregating of American schools which is happening right under our noses.

Albert Shanker would not approve of the touting of charters, or their "means" given what we now know. Would he?


I am pretty sure the effect of longer days would be to piss off students, especially in the KIPP factories where not a hand can be anywhere but at your side while you stand silently in line waiting for your classmates to finish in the lavatory.

School isn't daycare, nor should it be prison. Longer days do nothing, even though you think they can be helpful.

What is the point of your post? Are you saying charters' longer days may be helpful but so far they haven't proven to be?

Sorry I quoted you from a personal correspondence. I think you should respond to me here so I don't have to do that!


Thank you for your comments, TFT.

Selection bias ("creaming") is certainly an important factor, but the recent KIPP study tentatively shows that we can't simply dismiss effects as creaming. A future version of that study will include random assignment (controlling for pre-treatment differences between students), and we'll see how it turns out.

Al Shanker would have been - and was - horrified at attempts to use charter schools to undermine public education. The reason that he originally proposed them, however, was that he thought that schools didn't know nearly enough about how to help low-income children succeed, and that charters offered a way to test out different approaches. As it happens, most are neither very innovative nor very effective.

Thus, the point of the post is that the few charter schools that are nationally-lauded for their results are often used to justify the expansion of charter schools in general, even though most of them don't seem to work. I suggest that the effective few may achieve those results in some part because they have the kids for a lot more time. And if that's the case, we really need to know that.

I didn't offer an opinion as to whether more time is the right choice for schools. In part, my opinion would depend on whether future research more clearly demonstrates a "time effect" of sufficient size and persistence. If it does, I suppose the relevant follow-up questions might include:

1. What are the unintended consequences, such as teacher burnout/turnover?
2. Is the time being used just for test prep or more meaningful instruction/activities?
3. Is this an approach that should be considered only for students who are struggling or for a broader student population?
4. Are there more cost-effective solutions for schools that don't get millions in private donations?

Thanks again.