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Lesson 4.3

School Hours:
Is There Enough Time To Learn?

What do school assemblies, tests and birthdays have in common?

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Each year consists of about 6,000 waking hours. Children in America, on average, spend about 1,000 of them in school.

Most American children spend about six hours per day in school—fewer in lower grades and more in higher ones. Over the course of a year, students spend about 1,000 hours in class. How are those hours actually spent? Are they sufficient? Does changing the number of hours make any difference?

Yes, time matters.

Learning takes time. Places where school hours deliver more “time on task” are places where students tend to learn more. This is both obvious and provable: one elegant study found a clever way to verify the educational impact of time school time: it examined the effect of snow days (which vary in number by school and by year) on test results. Sure enough, when snow piles up, scores fall down. A day lost here or there actually does make a measurable difference.

For many students, the Pandemic inflicted the academic equivalent of a year of snow days.

The connection between time in school and learning has been deeply researched. More time focused on learning delivers more learning. The standard school day establishes a minimum baseline for the amount of time when students are supposed to have their brains turned on.

What is a Carnegie Unit?

A Carnegie Unit is 120 instructional hours

What exactly do we mean when we talk about school hours, or a school day, or a school week, or a school year? How much time is enough to add up to a “course”? Definitions like these matter when trying to compare programs.

About a century ago, the Carnegie Foundation played a pivotal role in setting standards for course credit, particularly for higher education. A Carnegie Unit is 120 school hours of instruction. The standard is still in use.

In recent years, critics including the leadership of Carnegie Foundation itself have argued that the standard has "outlived its shelflife" and should be replaced. Why? Because the measure fundamentally implies that "doing time" in a class is valuable, and systems have fossilized around it. Authentic learning should be the measure of educational attainment, not seat time.

International comparisons of school hours are tricky.

In the Ed100 blog
Homework: More time on task

Schools in different parts of the country and around the world use time in varying ways, with different school calendars and seasonal breaks. In an effort to permit comparisons, or at least to spur inquiry, the Organisation for Economic Co-Operation and Development (OECD) collects global data about school hours, most recently in 2023.

Schools in America are comparatively time-intensive, according the OECD data. American kids spend more time in classes than kids in most other countries do.

But the harder you scratch at the data, the harder it is to reach easy insights. The data is gathered by survey, and the methodology and even the questions vary from place to place. Grade level groupings used in the surveys are responsive to the different ways that schools are organized locally, and the surveys are massive.

What counts as school time?

International comparisons of education time are further complicated by the fact that not all learning time fits in the “official” system. In Japan and Korea, for example, formal school days are comparatively short, but there are more of them. Even more importantly, many families in these countries invest significant hours at private after-school and weekend “cram schools” that help their children prepare for standardized tests and college entry exams. Comparing only the official hours of school operation kind of misses the point.

A lot of learning can happen outside of official hours of school operation.

There’s an apples-and-oranges problem, too. Does it make sense to compare school hours spent in systems that are teaching different things? In Japan and China, students spend many hours learning to write characters accurately and legibly, a skill less important in English-speaking countries. The OECD survey suggests that most European countries invest about a tenth of primary-grade school hours in the study of international languages. America doesn't participate in this part of the survey, but the difference is obvious: few American primary schools teach international languages at all.

Comparing the use of time for education is tricky even within the United States. Like many other states, California generally requires 180 days of school per year, including a specified minimum number of total hours for each grade level. Some school districts are shifting to a four-day school week, though this strategy risks harming young students. Some districts conduct school five days per week, but routinely send kids home early to allow for faculty training or meetings.

Amanda Ripley, a noted education researcher and author, focused significant attention on the different ways that schools use time in different countries in her bestseller The Smartest Kids in the World and How They Got That Way.

How much time do students actually spend learning?

The true instructional value of school year is significantly shorter than it seems because not all school hours are instructional hours. A considerable amount of time is consumed by distractions like setting up, moving around, settling in, holding school events, assemblies, testing days, birthday celebrations and the like.

Not all school hours are instructional.

In the Great Recession (~2008-09), many California school districts cut five days from their school calendar. Which five? Not special days like testing days, assemblies, and birthday celebrations — those tend to be preserved. Almost by definition, the days lost were ordinary, unremarkable days with nothing special going on except teaching and learning.

Is instructional time the same for everyone?

In recession conditions, school districts that serve California’s highest-need students generally are more likely to have their school year cut in a recession. Low-income students and students of color are also more likely to lose days of instruction through school suspensions.

Time for relationships

School time is not just about academics. Students learn in connection with other students and with educators. Some charter school operators (like KIPP) regard a longer school day as a vital element of their program design. Beyond the academic effect of additional instructional time, a longer day in school may raise the likelihood that school serves as the central context for children’s social relationships.

This lesson was updated in December 2023.


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Questions & Comments

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user avatar
Bailey Barber February 26, 2021 at 11:01 am
I feel like Kids would learn more in the time given if they put effort into it. Most kids do not try because they do not like school. There is enough time to learn but, not enough student interest to learn.
user avatar
Victoria Robinson December 11, 2020 at 3:58 pm
Hello, do you mind sharing when this article was made?
user avatar
Jeff Camp December 11, 2020 at 5:35 pm
We update our lessons -- you can find the most recent update date in the fine print at the bottom! This particular lesson is scheduled for review and will be updated this month (December, 2020).
user avatar
Jamie Kiffel-Alcheh November 3, 2019 at 9:05 pm
New research (see Why We Sleep by Matthew Walker) makes a very convincing case for a late school start (particularly for teenagers).

Apart from this, I feel disappointed by the emphasis on test scores and de-emphasis on social development as well as other learning. What does a child learn through celebrating a holiday or a birthday with peers? This is valuable time for forming character. A snow day fills emotional reservoirs and gives time for the creative mind to refuel. More teaching does not equal more learning. And fewer breaks do not equal more productivity. Look at Europe’s vacation schedules or traditions of siestas as compared to the US, and see who is suffering more depression and anxiety.
user avatar
Lyra Exekiel December 8, 2018 at 6:49 am
Can anyone tell me who is the author?
user avatar
Jeff Camp December 9, 2018 at 3:21 pm
Hi, Lyra -- unless otherwise noted, the lessons and blog posts in Ed100 are written by Jeff Camp and Carol Kocivar.
user avatar
September 17, 2018 at 9:22 am
11th grade hit and I reflected on my life deeply. I looked at regrets. I became stressed and depressed. School did that to me. I didn't have time to look at family relationships, friends, girlfriends and even memories I could of made because I was so caught up in studying and trying to get the highest grade I could even if sometimes the highest I could achieve was a 75. It meant everything to go to college and make people happy but at the end of the day. It's not worth it. If I could change things, I would. I actually got so stressed out one day that I wrote down a lot of things I would change about our world if it were ever possible. My first change on the school section of those notes were to lower school hours and start school later in the day. It just feels right. I will homeschool my kids because they deserve their happiness and I don't want them to be pressured by a school system. That is just my take on things... but everyone has their own so feel free to discuss.
user avatar
Caryn September 17, 2018 at 9:48 am
Thanks for your comment. You may be aware that there is a bill waiting to be signed into law on Governor Brown's desk with the power to do just that--start school later in the day. It's SB -328. It sounds like starting school later would have made a difference in your life. By writing or calling the governor with your thoughts on this bill, you could impact the next generation. Change takes time but you have the ability to make a difference.
user avatar
Pamela Wright April 16, 2018 at 3:07 am
...and what about homework time?
user avatar
Jeff Camp - Founder April 17, 2018 at 12:59 pm
We did a "deep dive" on the question of homework in this blog post: Ed100 on Homework: More Time On Task
user avatar
kevin October 8, 2017 at 4:46 pm
I grew up in England, so my experience is the English Education System. Our daughter has made a smooth transition across, however we are constantly surprised with how when our son starts school he will be not only a year older than in England (and all his peers from home) but also for only three hours a day?! It really does not seem to make any sense.
user avatar
Lisette October 3, 2017 at 4:25 pm
California needs have all Kindergarten programs be a full day program vs a couple hours per day. Since Kindergarten programs have limited or eliminated homework, the full day of schooling is necessary.
user avatar
Caryn-C October 10, 2017 at 8:50 am
Since school isn't mandatory for children under age six in California, I don't think this will be prioritized.
user avatar
June 13, 2017 at 11:10 am
Just came across this article and am happy to see others who see the same issue. I'm from Australia and I see the same thing - less and less instructional hours and a shifting of the work no non school time and in effect parents. We operate on around 180 operating days per year with a variety of events reducing that. Over an operating week it barely equates to 20 instructional hours. Over a child's school life they spend barely 9% of thier total hours (asleep or awake) in face to face learning. That's not to suggest some of the other activities at school are not useful - it is to suggest 9% is woefully inadequate. By the way on average kids watch more television than that over a year. And what about all the infrastructure only open half the year - what a waste! I'm all for ulilising the infrastructure more and delivering more of what schools are supposed to do - teach kids. I find it enormously frustrating in Australia and interested to note it being observed elsewhere.
user avatar
Carol Kocivar October 27, 2016 at 4:26 pm
A report from the UCLA Institute for Democracy, Education and Access takes a careful look at instructional time loss. It finds:

California students attending high-concentration poverty schools are not able to access as much instructional time as the majority of their peers. It highlights ways that community stressors and chronic problems with school conditions lead to far higher levels of lost instructional time in these high schools.

Read the report:

user avatar
Mark MacVicar August 13, 2015 at 4:36 pm
Just a quick google turned up this interesting reference published in 2011
user avatar
Mark MacVicar August 13, 2015 at 5:24 pm
Another interesting article referencing a study by the Pew Research Center and another by OECD
user avatar
Janet L. April 20, 2015 at 7:13 pm
"... filtering out all the noise, students in a 180-day calendar only put in the equivalent of about 100 instructional work days per year..."
Oh my. "School events, assemblies, testing days, birthdays and the like" are significant to their learning. Certainly they don't teach to the test, but these events and activities teach our children in ways that should not be discounted. Social interaction, understanding and acceptance of other cultures, social responsibilities and more are taught during this "noise" and is significant in forming the adults and leaders these children will become.
I'm not opposed to longer school days or calendars, but I can't discount the advantage of the so-called "noise" our kids are experiencing.
user avatar
Tara Massengill April 17, 2015 at 7:19 pm
In my experience (both from going to school myself and having my child in school), I am unpleasantly surprised by the school hours for elementary schools in the SDUSD. In Tennessee, Texas, and Nebraska schools hours are from 8 am to 3pm (or something equivalent). Here in San Diego, it's 7:58 am to 2:20 pm (4 days a week), and 7:58 am to 12:05 pm on Wednesdays. I get that SoCal doesn't need to have built-in snow days, but it just doesn't seem like the kids are there long enough to learn all of the things they need to learn.
user avatar
hwilde April 2, 2015 at 9:40 am
To lb2vta- Many schools celebrate the 100th day for kindergartners. As they are learning to count to 100 this is fantastic opportunity to focus on this academic achievement in a way that engages students in fun and active ways.
To Sherry- Teacher collaboration and professional development does quite the opposite of reducing the number of effective instructional days. In fact research shows that educators who have time to work in teams or partnerships within and across grade level and fine tune their skills through professional development are more engage and excited about teaching and learning which translates to students who are more engaged and excited about learning within the context of the classroom and beyond.
user avatar
Susannah Baxendale January 17, 2019 at 12:30 pm
Agreed about the 100th day--the inventive ways kids (and their parents admittedly) found to illustrate 100 was wonderful.
user avatar
Mamabear March 19, 2015 at 11:41 pm
Why is the 100th day of school celebrated? Just curious if others do this? It seems to me that there is a tendency to go into second gear from this point to the end of the school year.
user avatar
Sherry Schnell January 22, 2015 at 10:38 am
Pulling teachers out of class during instructional time to engage in collaboration or professional development further reduces the number of effective instructional days.
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