We're still evaluating how well (or not) the system works, identifying problems, making improvements, and so on.
But here's some very preliminary analysis, by @andy_matuschak. Or, more precisely, it's me talking aloud about Andy's analysis!
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Here's the demonstrated retention versus the number of times each question in the essay has been reviewed. It takes a little work to unpack, but the basic point is: demonstrated retention appears to be increasing exponentially with the number of reviews.pic.twitter.com/KDVFyrWSj0
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To make this a little more concrete, at repetition number 5 (on the axis) a reader has reviewed all 112 questions in the essay 5 times.
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And the y axis shows the total demonstrated retention. So, for instance, after 5 repetitions, most readers are up around 3,000 days of demonstrated retention. That means an average of about 3,000 / 112 ~ 27 days per question in the essay.
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That's pretty good, I think. If you're anything like me, a few weeks after reading something you have only a hazy memory. By contrast, these people have, at very low cost (of which more below), got a month or so of demonstrated retention across more than 100 detailed questions
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This is the big hoped-for advantage of spaced repetition, and what makes it counterintuitive and unusual: you get _exponential returns_ for increased effort.
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It typically takes about 80 minutes of review time to get to 5 reviews. That's for an essay which takes about 3 hours to read - review for 80 extra minutes, and you can remember nearly all the details for about a month.
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We think that with just a little extra marginal effort you'll remember those details - the entire body of knowledge - for more like a year. That's the benefit of exponential returns. But the prototype hasn't been out long enough to test that.
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Here's the actual cumulative review time, rising roughly linearly (as we'd expect) with the number of repetitions.pic.twitter.com/GcbN9tjGoU
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Interestingly, as questions are repeated, people seem to get a little faster at answering them. Here's the marginal review time, showing a slight decrease.pic.twitter.com/2ieATLswPV
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That is, the marginal review time is going down, even though the time between reviews is increasing exponentially.
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Similarly, the accuracy is getting better with repetition, even with the time between reviews increasing exponentially. At least in this sense, people are becoming more fluent.pic.twitter.com/UeGQPdT1Di
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All very preliminary, of course, and there are many significant issues (esp. selection effects!) which we're working to address in other ways. Still, it's encouraging!
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One curious thing about this demonstrated retention vs review repetitions plot: at 5 reviews, almost everyone who sticks with it has 2.5k days of demonstrated retention. For a worst-case outcome, that seems v encouraging!pic.twitter.com/WBaeqe4bJ3
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Of course, "everyone who sticks with it" is a significant caveat. Maybe people who aren't going so well give up? We're investigating whether that might be the case or not.
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Another curious thing: the people scoring almost zero percent accuracy in the bottom left here. Again, something we're going to look into!pic.twitter.com/fz43OCYRM0
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I suspect, though, that it will turn out to be people using the system in an unusual way. E.g., in the body of the essay we advise people to delight in transgressive uses!pic.twitter.com/EimKoz5vXp
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(Someone running a citizen science project once told me they had a small stream of transgressive users - people who were completely ignoring the point of the project, and "doing things wrong" for their own delight.)
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Another fun tidbit: by repetition 5, almost everyone is getting 90+% of the questions right. It'd be nice to also better understand (a) what's happening for the other users; and (b) how honest people feel they are being (and actually are)?pic.twitter.com/HNm1t1WPph
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It just occurred to me that by strongly encouraging people to engage in transgressive uses, we're putting determined contrarians in a bind. To be transgressive they need to do exactly as we ask
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