Education & Future Learning · Project 7 of 12

The Ten Minutes That Teach

How much of a lesson survives three days

Teach five people the same ten minutes, test them twice, and count what seventy-two hours quietly deletes.

The calendar this needs: four fixed measurement days inside a fortnight — teach and test the first group, retest them seventy-two hours later, then teach and test the second group and retest them seventy-two hours after that — so the baseline teaching must start in week one and both retests must sit inside the same window of seventy-two hours plus or minus four.

Six weeksNo equipment on the paper route 20 written stepsMarked out of 20Free forever
The question

How much of one ten-minute lesson is still there in the people you taught three days later, and does changing one thing about how it is revised keep more of it?

Organisations spend enormous sums on training that nobody checks three days afterwards, and the field that does check — instructional design and learning measurement — is paid precisely because forgetting is expensive and invisible. A trainer who can show a retention curve instead of a satisfaction form is worth more than one who cannot, in schools, in hospitals, in factories and in software companies. The method here is the standard method: identical content, identical questions, identical gap, one variable changed, and the limits reported rather than buried.

Two acts. Find, then fix.

Every EAD project runs the same shape. The first act produces a number nobody in the room could previously state. The second act changes exactly one thing and proves whether that number moved.

Act 1 · Find
You take one small, self-contained thing you can teach fully in ten minutes, teach it identically to at least five people, and test them immediately with twenty short written items, one mark each, marked against a key you wrote first. Seventy-two hours later, give or take four hours, with no warning, no reminder and nothing to revise, you give the identical twenty items again, and the distance between the two scores is your finding.

A one-page costed problem statement carrying five lines: who was taught, the mean immediate score, the mean score at seventy-two hours, the mean of each person's own retained percentage, and what that loss is worth in minutes of teaching per week and hours or rupees per year at the rate teaching is actually paid for here. Beside it sits a two-point retention line for the group, marked with the number of people and the actual gap in hours each person was tested at.

Act 2 · Fix
You change exactly one thing about how the lesson is revised — a two-minute recap at day one, one practice question at day one, the learner explaining it back at the end, or a written summary in their own words — and you teach a second, comparable group the identical ten minutes from the same script. The same twenty items are asked at the same two moments, inside the same seventy-two-hour window, and marked to the same key by the same person.

Two lines on one chart, one per group, each running from the immediate score to the seventy-two-hour score, with the number of people on each, the mean of each person's own retained percentage for each group, the difference between them, and a written list of every way the two groups were not alike.

What actually gets measured

The numberthe share of an immediate test score still present after seventy-two hours, taken as the mean of each person's own retained percentage
BeforeFive or more people taught the same ten minutes from a written script, tested at once on twenty short written items marked one mark each against a key written before anybody answered, then given the identical twenty items in the identical order seventy-two hours later, give or take four hours, unannounced, with no revision in between. Work out each person's own retained percentage — their second score as a percentage of their own first score — and take the mean of those figures. That mean is the baseline, not one group mean divided by another, which lets a single high scorer stand in for the group.
AfterA second group of at least five, taught the same ten minutes from the same script by the same teacher, with one named change to how the material is revised, tested at the identical two moments inside the identical window with the identical twenty items, marked to the same key by the same person, and reported as the same mean of individual retained percentages.
The honest partA well-measured failure scores higher than an unmeasured success. If the number did not move, say so and explain why. With twenty items one mark is five points of a person's score, so no claimed difference smaller than five points means anything; and anybody who scored zero at once has no retained percentage, so leave them out and write down how many you left out.

If your household cannot run this

If you cannot find five people at home, cannot ask the same people twice, or have nowhere quiet enough to teach ten uninterrupted minutes, run the whole thing on school property with a member of staff. The staff member books one room, invites two groups of five from outside your own class, and stays in the room for every session and every retest. The script, the twenty items, the key, the codes, the consent and the seventy-two-hour window are exactly the same, and the work is marked exactly the same way. This is not a reduced version and it carries no smaller mark.

Every step, written out

Twenty steps in total — ten to find the number, ten to fix it. Pick the route that matches what your school actually has.

Hand-copied question sheets, a clock and squared paper produce the same retention figure; the sheets are identical because you copy them from one master, and the codes keep the scores private without any software.
You need: A notebook and a pen, plus one master sheet of twenty short items copied out by hand as many times as there are people, twice over · A clock or a watch with a second hand for the ten minutes, and a calendar for fixing the second test at seventy-two hours plus or minus four · An envelope for the marked sheets, and a separate folded page holding the code-to-name key, kept out of sight of everybody · Squared paper for the two-point retention lines, one per group, drawn to a stated scale · The consent sentence written at the top of every sheet and read aloud before every session · A written marking key on its own page, finished before the first sheet is handed out

  1. Choose the ten minutes

    40 minutes
    Pick one small, self-contained, neutral thing you can teach completely in ten minutes, and write the script.
    • List five candidate topics you could teach fully in ten minutes: a knot, the rules of a card game, how a lock works, the parts of a bicycle brake, five words of a language nobody in the room speaks.
    • Strike out any topic that appears on somebody's syllabus this term, and any topic touching belief, politics, family or money.
    • Write the ten-minute script word for word in the notebook, including the examples and the exact order, so the second group hears the identical lesson.
    • Read the script aloud twice against a clock with a second hand and cut or pad until it lands between nine and eleven minutes both times.
    • Write one sentence on why this topic is safe to test: it touches no mark, no belief and nobody's private life.
    Write down: The chosen topic, the safety sentence, and the full script with both timed lengths recorded.
    Finished when: The script runs to time twice in a row and contains nothing about anybody's beliefs, family, ability or graded work.
    Commonest mistake: Choosing something you know well and improvising around the script. Improvisation means the two groups get different lessons, and then nothing you measure afterwards means anything.

  2. Write the twenty questions

    70 minutes, plus 60 minutes of copying by hand
    Build one master test sheet of twenty short items with its marking key, so the identical paper can be given twice.
    • Write twenty short items that can only be answered by somebody who received this lesson, one mark each, with no half marks anywhere; twenty items rather than five is what makes a score move in steps of five points instead of twenty.
    • Write the marking key on its own page, stating exactly what earns a mark and what does not, before a single answer exists.
    • Copy the master sheet out by hand once per person for the first test and again for the second, with a code box at the top and no name line.
    • Give one copy to a person who has not had the lesson; their score tells you how much of your test can simply be guessed.
    • Write both test moments on the calendar now: immediately after teaching, and seventy-two hours later, plus or minus four hours, with the same window written down for the second group.
    Write down: The master sheet of twenty items, the marking key page, the untaught person's score out of twenty, the count of copies made, the two fixed test moments and the stated window.
    Finished when: Somebody who never had the lesson scores near zero, and the key decides every mark without you having to think.
    Commonest mistake: Copying the sheet from memory the second time and changing a word. Copy every sheet from the one master; a reworded question is a different question and the comparison dies with it.

  3. Ask and consent

    40 minutes
    Recruit at least five people, take consent in words, and give everybody a code instead of a name.
    • Find at least five people who can give you ten minutes now and five more minutes in three days, and ask each one face to face.
    • Read the consent sentence at the top of the sheet aloud to each person: this is a study about forgetting, not about you; your score is never shown to anyone; you can stop at any moment and I will destroy your answers.
    • Give each person a code, tell them what it is, and write the code-to-name key on a folded page kept apart from the sheets.
    • Record consent as a tick, a code and a date, and note that consent will be asked for again at the second test.
    • Write one neutral line per person on two facts they supply themselves: how much of the topic they already knew, and whether the lesson is in their first language. You do not judge anybody's reading, ability or anything else about them.
    Write down: The consent record by code and date, the folded code page kept apart, and the one-line profile of each participant.
    Finished when: Five or more people have consented aloud, hold a code, and know they can stop; no name sits anywhere near a score.
    Commonest mistake: Recruiting only the people who are good at tests because they are easy to ask. Write down who you asked and who declined, because a group of five willing friends is a limit you must report, not hide.

  4. Teach and test now

    45 minutes
    Deliver the ten minutes from the script and test everybody immediately.
    • Teach from the script without adding examples, without answering extra questions, and time every session against the clock.
    • Hand out the copied sheets the moment the lesson ends, with no discussion in between and the participants seated apart.
    • Check each sheet carries a code and not a name before you collect it, and put the collected sheets straight into the envelope.
    • Mark every sheet against the key page and write the score against the code in the notebook, never against a name.
    • Tell everybody truthfully that there is nothing to revise and that they should carry on as normal.
    Write down: The immediate score out of twenty for each code, the exact clock time each person finished the lesson, the timed length of each session, and any deviation from the script.
    Finished when: Every code has a first score out of twenty and a recorded finishing time, the sessions ran within one minute of each other, and every collected sheet is anonymous.
    Commonest mistake: Answering one good question during the lesson and giving that person extra content. Write the deviation down and report it rather than pretending the lesson was identical when it was not.

  5. Test at seventy-two hours

    40 minutes, three days after the lesson
    Give the identical twenty items again inside the stated window, unannounced, and measure the drop.
    • Wait the full seventy-two hours, plus or minus four, without reminding anybody, handing out anything or discussing the topic in front of them; a window rather than an exact hour keeps the second test off a school night for people who cannot sit it then.
    • Ask each person again whether they are willing, and record anybody who declines as a withdrawal, removing their first score and destroying their sheet.
    • Hand out the second set of copies from the same master, identical items in the identical order, and mark to the same key.
    • Ask each person one question afterwards and write the answer down: have you thought about this or talked about it since.
    • Work out each person's own retained percentage longhand — their second score as a percentage of their own first score — then take the mean of those percentages, and write the actual gap in hours beside every code.
    Write down: The second score out of twenty per code, the per-person drop, each person's own retained percentage, the mean of those percentages, and the actual gap in hours for every person, not only the late ones.
    Finished when: You can state one number aloud: the mean of each person's own retained percentage after three days, with every gap in hours written down beside its code.
    Commonest mistake: Letting the gap slip to five days because somebody is busy. Stay inside seventy-two hours plus or minus four, write the actual gap in hours beside every person's score, and use the identical window for the second group, because a mixed gap makes the two groups incomparable later.

  6. Name the loss

    50 minutes
    Finish the costed problem statement on one page and choose the single change you will test.
    • Write five lines: who was taught, the immediate mean out of twenty, the three-day mean out of twenty, the mean of each person's own retained percentage, and what that loss is worth in minutes of teaching per week and in hours or rupees per year at the rate teaching is actually paid for here — and add in the same line that the yearly figure assumes every teaching week is like this one, which it is not, since holidays, revision weeks and repeated topics all change it.
    • Draw the group's two points on squared paper to a stated scale as one two-point retention line, labelled with the number of people and the range of gaps in hours, with the finding as the title.
    • List three possible changes: a two-minute recap at day one, one practice question at day one, the learner explaining the lesson back at the end, a written summary in their own words.
    • Choose one and write: 'The second group gets X and nothing else changes; I expect retention to rise from A per cent to B per cent.'
    • Read the page aloud to one person who was not involved, and write down the first thing they did not understand.
    Write down: The one-page costed problem statement, the three candidate changes, the chosen change as one testable sentence, and the known limit stated in advance.
    Finished when: Somebody who was not there reads the page once and repeats your percentage-lost figure back correctly.
    Commonest mistake: Changing the topic as well as the revision because the first lesson felt weak. One variable moves; if the lesson was weak, it stays exactly as weak for the second group.

  7. Match the second group

    40 minutes
    Recruit and consent a second, comparable group of at least five, and record honestly how they differ from the first.
    • Recruit at least five people who had no contact with the first group's lesson and who have not heard the topic discussed.
    • Read the same consent sentence aloud, record consent by code and date, and use a separate letter series so the two groups are never mixed up.
    • Write the same one-line profile from the two facts each person supplies themselves: how much of the topic they already knew, and whether the lesson is in their first language.
    • Rule two columns on one page, one group each, and write every way the groups are not alike under a heading that says 'limits'.
    • Write both test moments and the exact moment of the change on the calendar, using the identical seventy-two-hour window the first group had, and copy out the sheets for both tests from the same master.
    Write down: The second group's consent record, profiles, the two-column comparison of the groups, and the written list of differences.
    Finished when: Five or more people have consented, hold codes in a separate series, and the ways the groups differ are written down before any teaching happens.
    Commonest mistake: Claiming the groups are the same because they are the same size. Same size is not same group; write what actually differs and say plainly that it limits what you can conclude.

  8. Teach group two

    45 minutes
    Deliver the identical ten minutes to the second group and test immediately with the identical twenty-item sheets.
    • Read the same script word for word, timed against the same clock, adding nothing and answering no extra questions.
    • Deliver the change here if it belongs at teaching time, such as the learner explaining it back or writing a summary in their own words, and time that separately.
    • Hand out the copied sheets the moment the lesson ends, collect them into the envelope, and check every sheet carries a code.
    • Mark against the same key page and write the scores in the notebook under the second group's codes.
    • Compare the two immediate means longhand and write one line on whether the groups started level; if they did not, say so now rather than at the end.
    Write down: The second group's immediate score out of twenty per code, the timed session length, the time taken by the change, and the comparison of the two immediate means.
    Finished when: Every code in the second group has a first score, and you have stated in writing whether the two groups started level.
    Commonest mistake: Teaching the second group better because you have had practice. Read the script; a lesson delivered more warmly the second time is a second variable you cannot separate out.

  9. Change and retest

    50 minutes across three days
    Deliver the change at the agreed moment, retest inside the same window, and draw the two retention lines side by side.
    • Deliver the change exactly as written and at the agreed hour, timing it and recording who received it and who was missed.
    • Test seventy-two hours from the lesson, plus or minus four, using the identical window the first group had, asking consent again, recording any withdrawal and writing the actual gap in hours beside every code.
    • Mark to the same key, then draw both groups on one sheet of squared paper as two retention lines of two points each, from immediate to seventy-two hours, each labelled with its number of people, both on the one scale of per cent retained so no second unit shares the axis.
    • Work out the mean of each person's own retained percentage for the second group, write the difference between the two group figures as a number, and say plainly that with five people per group and one mark worth five points, a difference smaller than five points settles nothing.
    • List every confounder: different people, a different day of the week, one group taught in a noisier room, somebody who discussed the topic with a friend, a lesson that ran a minute long.
    Write down: The second group's seventy-two-hour scores out of twenty, the actual gap in hours per code, both mean retained percentages, the two-line chart, the difference between them, and the confounder list.
    Finished when: You can state both mean retained percentages, the difference between them, and at least two reasons that difference might not be caused by your change.
    Commonest mistake: Reporting the difference as proof. With five people per group a difference can easily be the people rather than the method, and one mark on a twenty-item test is already five points, so report the number and the uncertainty in the same breath.

  10. Share and reflect

    60 minutes
    Publish the finding without naming anybody, defend it to real people, and record what you would keep.
    • Answer unseen questions out loud for ten to twelve minutes in front of two witnesses who sign and date the page: the topic, both groups, the two retention lines, the one change, the difference and the limits, using codes and never names. There is no recording on this route.
    • Read the one-page explainer to three people who teach or train and write down what each of them said.
    • Hand the two-line page to the teacher or trainer you interviewed with one question: what would you have controlled that I did not.
    • Tell every participant their own result privately if they want it, tell them nobody else has seen it, and tear up the code page in front of one witness who signs a line saying it was destroyed. Nothing is burned.
    • Complete the relations ledger with ten codes, roles, dates and what each person replied.
    Write down: The defence, signed and dated by its two witnesses, the one-page explainer, the witnessed and signed note recording that the code page was torn up, and the relations ledger holding ten coded relationships.
    Finished when: Ten relationships are logged with dates and replies, and no participant's score can be traced back to a name by anybody, including you.
    Commonest mistake: Showing the retention lines with a name or a recognisable description beside a low score. Codes only, in the defence, the explainer and the ledger, with no exceptions for people who say they do not mind.

What the student hands in

Nine pieces. Together they are the folder a parent can sit down and read.

1. Question cardOne card naming the ten-minute topic, how many people were taught, the twenty-item test and the window in hours, and the question: how much survives seventy-two hours, and does one change to revision keep more.
2. Expert interview packFive written questions for a teacher, trainer, tutor or learning researcher, your first two-point retention line attached as one page, the date the request was sent by your teacher from the school address, and the reply recorded word for word.
3. Evidence logThe script, the twenty items, the marking key written before any answer, the consent record by code and date, every score out of twenty against its code, each person's own retained percentage, and the actual gap in hours for every person tested.
4. Failure logThe person tested at ninety hours and so outside the stated window, the withdrawal, the lesson that ran twelve minutes, the participant who discussed the topic with a friend, and what each did to the comparison.
5. The buildThe study instrument itself — script, twenty items, marking key and consent wording — together with the two-point retention lines running from the immediate score to the seventy-two-hour score for both groups, per cent retained being the only unit on the axis.
6. One-page explainerOne page a stranger reads in ninety seconds: the topic, the mean of each person's own retained percentage, the one change, the second group's figure, the difference, the fact that one mark is five points so smaller differences mean nothing, and what a study this small cannot tell anybody.
7. Identity cardA name and a one-line promise for the revision method you tested, so a teacher can ask for it by name, plus the single sentence you want repeated by somebody who has just finished teaching.
8. Relations ledgerTen coded entries with roles, dates and replies: E1 the professional, A1 to A3 the people the forgetting affects, P1 to P3 the peers who checked your key, and R1 to R3 the people you sent the chart to who answered. The sheet matching codes to names is held by the school and destroyed after moderation.
9. The defenceTen to twelve minutes of unseen questions answered live in front of two witnesses who sign and date the page, using codes and no names: the topic, both groups, both two-point retention lines, the one change, the difference, and the limits of five people per group accepted without argument. A recording is optional evidence and never the requirement, and on the No-Tech route there is no recording at all.

The expert they have to find

Ten logged relationships are required before this project can be marked. One of them is an expert, and this is who.

A teacher, a corporate or vocational trainer, a private tutor or a learning researcher — somebody who has to make material stick and finds out when it does not.

How to find one

Think in institutions and roles rather than in named people: a nearby school or college and its head of department, the training department of a hospital, a bank or a factory where one course is run again and again, the education department of a university, or a tutoring centre and its senior tutor. You name the institution and the role you want. Your teacher makes the approach from the school address, and any call or written reply comes back through the school. You do not search for an individual and you do not write to anybody yourself.

What to say

Dear [name or role], I teach at [school]. One of my learners has taught the same ten minutes to [number] people, tested them on twenty short items straight away and again seventy-two hours later, and measured how much of the lesson survived. Could you spare fifteen minutes — on a call with me present, or by written reply, whichever suits you? Their five questions are below.

What to ask

  • When you teach something once, how much do you expect to be there three days later, and what makes you think that?
  • What do you do differently for the material you cannot afford to have forgotten?
  • How would you check whether your teaching worked, if nobody gave you a test to use?
  • What makes a test question a fair test of a lesson rather than a test of general knowledge?
  • If you had two small groups and one change between them, what would you be most worried about in the comparison?

If no reply comes, the learner submits the questions exactly as they were sent, the dated record of the attempts, and one named published source in place of the answers, and that route scores full marks. The gate is a serious, documented approach, never a reply you managed to extract from somebody.

The defence

Eight of the twenty marks. A student who cannot answer these has not finished, however good the artefact is.

  • Would the second group have remembered more anyway without your change, and how do you know?
  • Your two groups were different people. Name every way they differed and tell me which difference could have produced your whole result on its own.
  • Five people per group. Convince me that is enough to say anything, and tell me what number would have satisfied you.
  • You averaged each person's own retained percentage rather than dividing one group mean by the other. Explain why, and tell me what the second figure would have shown instead.
  • Your test has twenty items, so one mark is five points of a person's score. What is the smallest difference between your two groups you are willing to call real, and why that one?
  • Not everybody was tested at exactly seventy-two hours. Give me the actual gap in hours for every person and tell me what the spread does to the comparison.
  • Somebody in the second group says they thought about the topic on day two. What does that do to your finding, and what did you do about it?

How far a student can take it

starterYou teach the same ten minutes to five people, test them immediately and again at seventy-two hours with the identical twenty items, and report the mean of each person's own retained percentage with everybody's consent recorded.
practitionerYou choose and defend your own topic and sample, write the marking key before any answer exists, cite anything you borrowed, and produce one chart a stranger reads correctly without you explaining the axes.
researcherYou write the whole protocol before teaching, justify five people, twenty items and a seventy-two-hour window rather than fewer, coarser or longer, and quantify what a single marker, a small group and volunteer recruitment do to your result.
contributorYou set your own measured retention figures against published work on spaced revision, quoting each published figure beside yours rather than in place of it, defend your controls to one professional who disagrees, and publish the script, the items, the key and the anonymised scores through your school, where your school agrees they may be published.

If you want to go further

Run a third group with a second revision change and put all three retention lines on one axis, keeping every other condition identical.

When it goes wrong

  • If nobody will be taught by you - then teach the ten minutes to people who already owe you five minutes, such as the family you live with and one neighbour, going with an adult who stays within sight if the neighbour is not in your own home, and report plainly that a convenience sample is what you had.
  • If the household or the site says no - then ask your teacher for a room on school property and a member of staff to sit in, run the identical method there with two groups from outside your own class, and say in the write-up where it was run; it is marked exactly the same.
  • If your two groups look the same - then report the null result, check first whether the change was actually delivered to every person and at the agreed hour, and put the delivery record beside the chart.
  • If you could not test inside the window - then record the actual gap in hours for every person, apply the identical window to the second group, and report the window you used rather than the one you meant to use.
  • If you run out of time - then keep both groups and shorten nothing about the method, dropping the third teaching session or the stretch rather than the seventy-two-hour test, because without the second test there is no finding at all.

Before you start

Safety and consent.
  • Consent every time, in words, before every session and before every test. Each person is told that this is a study about forgetting rather than about them, what will happen to their answers, and that they may stop at any moment, refuse the second test, or ask for their answers to be destroyed, with no reason given and nothing said about it afterwards.
  • Scores stay private. Everybody becomes a code before anything is written down; no name goes on an answer sheet, into a form or onto a chart; nobody sees anybody else's score; nobody is ranked, compared aloud, told they did badly or told who scored highest. The page linking codes to names stays with you, out of sight, and is destroyed when the project ends.
  • Never test anybody on work they are being formally graded on. Choose a small neutral topic that touches no real mark anywhere, because a poor result here must never reach a report, a file or a mark book. The topic is never personal, religious or political, and no question asks about anybody's beliefs, family, income or ability.
  • No pressure and no rewards that make refusal awkward. At the second test, ask again rather than assuming, and record anybody who declines as a withdrawal, removing their first score from the analysis and saying so in the report.

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