A Little Calculation

Can I have a few seconds? Researchers have been videotaping classes, taking notes, making an estimate of how much time children are actually receiving instruction, as opposed to walking, listening to announcements, handing in or receiving papers, and so forth; it comes to 90 minutes of actual instruction per school day.

But even that tally is not quite accurate – some of that 90 minutes of instruction is of little value to particular students, since the material is already understood. “Did that already, about three times. Can we move on already?” And for others, the material is incomprehensible.

So, I did a back-of-envelope calculation and came to a figure which could be a little off, but I guesstimate that the average classroom, in one year, wastes (in total, for all 30 or so children), about a gigasecond of their time.

Oh, so sorry. Did you just spit out your coffee? Did I forget the leg-pulling warning? I must advise you to finish swallowing and put your drink or sandwich down. I’ll wait.

A gigasecond is one billion seconds.

A year is about 31.5 million seconds. We can be more exact: 60*60*24*365 = 31,536,000 seconds. Can twiddle this for leap years and leap seconds, but that’s close enough for an approximate¬† calculation.

Divvy that into a billion, and we have 31.79 years … you see where this is going, don’t you?

31 is roughly the number of students in a class … so, one year wasted per year per child.

Yes, it’s harsh. I sincerely apologize to every hard-working teacher who is trying to do something useful – and yes, some of you are very, very much appreciated from the bottom of my heart, and from many other students who are grateful for those of you who do stand out.

But … why did I have to explain any of this? It’s a simple calculation, and you have had twelve years of instruction in math, which most of you hate. What’s wrong with this picture?

A 30-something friend, with an impressive string of letters in STEM disciplines, shared a thought. He and his friends, some of the brightest people in Southern California, still wake up with nightmares about their K-12 school years.

If it’s that bad for the “good” students, the best and brightest, we might want to try something different. I’d go back to basics: if 90 minutes or less of instruction is all we have to work with, what if those 90 minutes were more efficient? What if, instead of five or ten useful minutes (from the perspective of the child), we find inexpensive (time-wise) methods to find out what is known and unknown for that particular student, and provide only that which is unknown?

2 thoughts on “A Little Calculation”

  1. I agree with the spirit of this post, but I don’t see how it’s mathematically possible to waste more than 1 year per child per year, even if each child spent equal to 1 year IN school per year (they don’t–typical schools run roughly 180 days per year, and those aren’t 24-hour days, but 7 to 8-hour days).


    1. I was spoofing the educators – but consider this: children must not only attend school, but travel to and fro, and must give up time to do homework, and they effects of school taint the rest of their days as well. But as you say, it’s a spoof, not a mathematical treatise. Thanks!


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