Notes on a recent wave of spam 2018-06-14T15:39:51.090Z · score: 11 (7 votes)


Comment by rossry on When is pair-programming superior to regular programming? · 2019-10-10T13:09:51.406Z · score: 10 (6 votes) · LW · GW

It's easy to play armchair statistician and contribute little, but I want to point out that the empirics cited here are effectively just anecdotes. The paper studies 13 pairs and 13 individuals in three assignments in one class at UUtah. Its estimate of relative time costs is only significant to ~ because development time has variance of (if I backsolved correctly) 65%, which...seems about right. Still, it seems like borderline abuse of frequentist statistics to argue that a two-tailed p<0.05 should be required to reject the hypothesis that pairs finish projects in half the wall-clock time of individuals (which is the null the analysis assumes).

That said, the author correctly identifies that quality matters significantly more than speed. The quality metric, however, is "assignment tests passed" in throwaway academic projects, eliding the questions of what quality failures would or wouldn't be caught by the review / CI workflows that an industrial project would be going through anyway.

So, finger to the wind, this study feels like it suggests that a pair spends 15% more person-hours (once they get used to each other) before turning their schoolwork in, and do 15% more of the work of the assignment than a student working alone. Consistent with the higher reported work-enjoyment numbers! Definitely a stronger showing than I would have guessed! But definitely not well-abstracted by "no significant result for time; significant improvement for quality".

What am I missing here?

Comment by rossry on Eukryt Wrts Blg · 2019-09-29T01:59:11.495Z · score: 3 (3 votes) · LW · GW

(continued, to address a different point)

B and C seem like arguments against "simple" (i.e., even-odds) bets as well as weird (e.g., "70% probability") bets, except for C's "like bets where I'm surer...about what's going on", which is addressed by A (sibling comment).

Your point about differences in wealth causing different people to have different thresholds for meaningfulness is valid, though I've found that it matters much less than you'd expect in practice. It turns out that people making upwards of $100k/yr still do not feel good about opening up their wallet you give you $3. In fact, it feels so bad that if you do it more than a few times in a row, you really feel the need to examine your own calibration, which is exactly the success condition.

I've found that the small ritual of exchanging pieces of paper just carries significantly more weight than would be implied by their relation to my total savings. (For this, it's surprisingly important to exchange actual pieces of paper; electronic payments make the whole thing less real, ruining the whole point.)

Finally, it's hard to argue with someone's utility function, but I think that some rationalists get this one badly wrong by failing to actually multiply real numbers. For example, if you make a $10 bet (as defined in my sibling comment) every day for a year at the true probabilities, the standard decision of your profit/loss on the year is <$200, or $200/365 per day, which seems like a very small annual cost to practice being better calibrated and evaluate just how well-calibrated you are.

Comment by rossry on Eukryt Wrts Blg · 2019-09-29T01:38:57.423Z · score: 3 (3 votes) · LW · GW

Hi! I've done a fair amount of betting beliefs for fun and calibration over the years; I think most of these issues are solvable.

A is a solved problem. The formulation that I (and my local social group) prefer goes like "The buyer pays $X*P% to the seller. The seller pays $X to the buyer if the event comes true."

The precise payoffs aren't the important part, so long as they correspond to quoted probabilities in the correct way (and agreed sizes in a reasonable way). So this convention makes the probability you're discussing an explicit part of the bet terms, so people can discuss probabilities instead of confusing themselves with payoffs (and gives a clear upper bound for possible losses). Then you can work out exact payoffs later, after the bet resolves.

(As a worked example, if you thought a probability was less than 70% and wanted to bet about $20 with me, if you "sold $20 at 70%" in the above convention, you'd either win $2070%=$14 or lose $20-($2070%)=$6. But it's even easier to see that you selling a liability of $20p(happens) for $2070% is good for you if you think p(happens)<70%.)

You've right that odds are a terrible convention for betting on probabilities unless you're trying to hide the actual numbers from your counterparties (which is the norm in retail sports betting).

Comment by rossry on Long-term Donation Bunching? · 2019-09-29T01:01:03.867Z · score: 1 (1 votes) · LW · GW

I also think that if the "sixth friend" donates $10k in line with each other friend's values and beliefs (as a result of social expectation, not contract), then there's no particular benefit to being the one who has to handle the money, and you don't need to trust in multi-year commitments.

Comment by rossry on Long-term Donation Bunching? · 2019-09-29T00:53:06.260Z · score: 1 (1 votes) · LW · GW

Your suggestion is correct, though it seemed too messy (and nonessential) to explain for the sake of an off-the-cuff proposal. I added a footnote to clarify this above, though.

Comment by rossry on Long-term Donation Bunching? · 2019-09-28T00:41:56.340Z · score: 1 (1 votes) · LW · GW

Proposal: Five friends in this situation write $10k checks[1] to a sixth. They all have a long chat about their altruist values and beliefs. The sixth donates $60k to a variety of EA causes.

Question: Just how likely / unpleasant would the ensuing IRS audit be?

(There's also a micro-donor-lottery version of this, except the individual contributions are personal gifts and the full $60k is a charitable donation.)

[1] Actually, you want this to be something like $7k, since the tax deduction from donating is worth [your marginal income tax rate] on the amount, roughly 30%. Formally, $10k less the tax benefits from donating $10k.

Comment by rossry on Free Money at PredictIt? · 2019-09-27T07:42:56.215Z · score: 8 (4 votes) · LW · GW

That's exactly correct. It's a standard taxation-begets-misallocation scenario.

For reference, PI's current rules have this effect to roughly 0-3% per contract, potentially adding across multiple contracts in a bundle. Prices closer to 50% are worse (though prices further away have their own biases, as Zvi explains).

Comment by rossry on Free Money at PredictIt? · 2019-09-27T07:32:02.184Z · score: 6 (4 votes) · LW · GW

Yeah, Zvi is (unsurprisingly) right; the change in margining rules (after I wrote that post) makes it much better to sell the low-value contracts, and the withdrawal fees amortize if you're in for the longer term.

To new rules, and on the back of my envelope, Zvi's 12% "arbitrage" is something like a few percent good: maybe it covers withdrawal fees on its own, and likely will do so after a few rounds. The opportunity cost of capital is a whole 'nother issue...

I also strongly endorse the punchline that trading (even on the margins of trading costs) is some of the best rationalist training you can find.

Comment by rossry on Free Money at PredictIt? · 2019-09-26T23:18:07.859Z · score: 1 (1 votes) · LW · GW

Huh, I hadn't noticed that they didn't tie up the potential fees on your winnings. Hypotheses:

  • bug introduced when they moved from gross margining to net margining years and didn't reconsider fees withholding
  • doesn't actually matter; they don't give up ~anything by letting some people carrying small balances make free trades
  • it's really hard to abuse this into free trades repeatedly
  • the withholding here is too complicated and feel-bad to explain
  • other
Comment by rossry on Taxing investment income is complicated · 2019-09-23T12:00:36.673Z · score: 3 (2 votes) · LW · GW

Ah, that makes sense.

Separately, I'm not entirely convinced by that second bullet point -- it seems like a non-omniscient state planner in a non-stationary environment would benefit from being able to determine the desired level of redistribution after the wealthy have accrued their income as wealth, rather than needing to get it right as they earned it.

(I'm assuming away the confiscatory impulse here, naturally; in practice, the political economy of confiscation causes serious issues for deferred decisions about distribution like this.)

Comment by rossry on Taxing investment income is complicated · 2019-09-22T23:40:55.720Z · score: 1 (1 votes) · LW · GW

Can you explain more why the tax rate on the risk-free-rate portion of investment income should be 0? A positive rate here implements a proxy wealth tax (without raising the reporting problems of a direct wealth tax), and a nonzero wealth tax might be part of an optimal tax policy (e.g., for the lots-of-small-taxes argument, if no other reason).

(I'm not sure that this is right, and am mostly asking this question from a stance of exploratory uncertainty.)

Comment by rossry on Taxing investment income is complicated · 2019-09-22T23:35:36.191Z · score: 2 (2 votes) · LW · GW

To be clear, this is the low-order approximation around 0; as explained in Paul's link (sibling to this) the effect away from zero involves the shape of the supply and demand curves through the relevant region of prices (and the stated claim holds when they're linear).

Comment by rossry on Spiracular's Shortform Feed · 2019-09-12T22:53:59.965Z · score: 2 (2 votes) · LW · GW

My guess is that one gets a reasonable start by framing more tasks as self-delegation (adding the middle step of "decide to do" / "describe task on to-do list" / "do task"), then periodically reviewing the tasks-competed list and pondering the benefits and feasibility of outsourcing a chunk of the "do task"s.

Creating a record of task-intentions has a few benefits in making self-reflection possible; reflecting on delegation opportunities is a special case.

Comment by rossry on Negative "eeny meeny miny moe" · 2019-08-21T14:55:24.967Z · score: 1 (1 votes) · LW · GW

Oh, you're right. The net incentive to catch cheaters is actually... 1/(k(k-1)^2), then? The relative incentive story is worse, though still better in total than the positive version, and better still if you assume a constant-size disincentive to be caught cheating.

Comment by rossry on Negative "eeny meeny miny moe" · 2019-08-20T10:49:46.809Z · score: 1 (1 votes) · LW · GW

Another (related?) advantage is that the incentives to manipulate and catch manipulation are much better balanced with the negative ("you're out") version. Consider:

  • Perfectly cheating in the positive version improves your chances of winning by (n-1)/n, and stopping you from doing so improves each other person's chances by 1/n.
  • Perfectly cheating in a round of the negative version improves your chances of winning by 1/(k(k-1)), where k is the number of people in to start the round. Stopping you from doing so improves each other person's chances by the same amount.
  • The total (summed) incentive to manipulate in the negative version is (n-1)/n, the same as in the positive case.
Comment by rossry on Open & Welcome Thread - August 2019 · 2019-08-13T13:17:23.744Z · score: 4 (6 votes) · LW · GW

(Disclaimer: I'm a financial professional, but I'm not anyone's investment advisor, much less yours.)

You mention diversity as an advantage because it reduces your risk, but this framing is missing the crucial point that you can transmute a portfolio that's 0.5x as risky as your baseline to one that returns twice as much as your baseline. (Wei_Dai mentions this, but obliquely.) The trick is to use leverage, which is not as hard to get (or as expensive, or as complicated) as you think.

To be explicit about it: if you increase the per-dollar riskiness of your portfolio without increasing the per-dollar expected value, then after you leverage it down until it's at the optimal level of risk for your utility function (which you were going to do, right?), you will have lower expected returns.

The relevant question is "how much lower?" (which is precisely to say "how much does it increase your per-dollar risk?"), which I answer in my response to Wei_Dai (nephew to this). The answer turns out to be "very little", but in order to get there, you have to be asking the right question first.

Comment by rossry on Open & Welcome Thread - August 2019 · 2019-08-13T13:13:58.042Z · score: 4 (2 votes) · LW · GW
I don't have a good intuition about how costly this actually is in practice, if you only play with 10% of your portfolio.

tl;dr extremely little.

Here's some numbers I made up:

  • Let the market's single common factor explain 90% of the variance of each stock.
  • Let the remaining 10%s be idiosyncratic and independent.
  • Let stocks have equal volatility (and let all risk be described by volatility).

Now compare a portfolio that's $100 of each of a hundred stocks with one that's $90 of each of a hundred plus $1k of another stock. (I'll model each stock as 0.75 times the market factor plus 0.25 a same-variance idiosyncratic factor.) Compared to a $10k single-stock portfolio...

  • the equal-weighted portfolio has like
  • the shot-caller's portfolio has like

...for an increase in of 4.5 basis points. So, pretty negligible.

Even if the market's single factor explains only half of the variance of each stock, the increased risk of the shot-caller's portfolio is just 40 basis points ( vs ). In the extreme case where stocks are uncorrelated, the increased risk is +34.5%, though I think that that's unrealistically generous to the diversification strategy.

Since an increase in volatility-per-dollar of basis points means that you give up basis points of your expected returns, I'm going to say that this effect is negligible in the "10% of portfolio" setting.

Comment by rossry on Does human choice have to be transitive in order to be rational/consistent? · 2019-08-11T05:29:46.881Z · score: 1 (1 votes) · LW · GW

Can you define "rational/consistent"? The terms are a bit overloaded, especially in this community, and making your definition precise is itself most of the answer to your question.

For example, you give some good examples of nontransitive decider-actors, and if some of them are "rational", then nontransitive preferences can be rational, as you point out. Alternatively, one definition of "consistent" is that a decider-actor will always reach the same decision when it has the same information, regardless of what other options it has previously rejected, which requires transitive preferences.

Comment by rossry on How can we respond to info-cascades? [Info-cascade series] · 2019-08-05T11:08:29.548Z · score: 1 (1 votes) · LW · GW

Is the idea something like: the actor themself is uncertain about the value of the project, and the kickstarter also helps them find out whether it's worth doing

Nope! The paper's model for this result assumes that the value conditioned on success is known to the proposer, so that the proposer's only incentive is to maximize their own profits by setting the payout odds and threshold. The (non-obvious to me) result that the paper proves is that this coincidentally minimizes the probability of up-cascades:

A higher decision threshold excludes more DOWN cascades while it is less likely to be reached. We show that the concern about potential DOWN cascades dominates the concern about likelihood to reach the target. To maximize the proceeds, the proponent endogenously sets the target to the smallest number that in equilibrium completely excludes DOWN cascades in the same spirit as Welch (1992), with the caveat that the proponent utilizes both price and target to achieve this. Consequently, with endogenous issuance pricing, there is no DOWN cascade which stops private information aggregation, and good projects are always financed while bad projects are never financed, when the crowd base N becomes very large. In other words, financing efficiency and information aggregation efficiency approaches the first best as N grows bigger, despite the presence of information cascades.

Comment by rossry on Zeno walks into a bar · 2019-08-04T09:12:12.500Z · score: 10 (6 votes) · LW · GW

My (uninformed) guess is "humor, of the slightly mind-sharpening sort".

Comment by rossry on Proposed algorithm to fight anchoring bias · 2019-08-03T06:41:02.812Z · score: 11 (5 votes) · LW · GW

Hypothesis: (formed before running the test below) "clearly too high" will be more of an overestimate than "clearly too low" is an underestimate; most midpoints will be high; this will bias estimates high (especially through repeated self-anchoring to high midpoints).

Anecdata: I tried using this method to estimate the number of gates in Hong Kong International Airport. (I'm currently standing in a line in HKIA, and have flown through it at least a dozen times in my life.)

  • 40 ~ 10,000
  • 40 ~ 5,020
  • 40 ~ 2,530
  • 40 ~ 1285
  • 40 ~ 662 (maybe 351 is neither obviously too high or too low, so I should take it? or maybe it's slightly high and so...)
  • 40 ~ 351 (195 I don't have a strong opinion about, so I'll take it)

So, depending on how I decide to stop, I get estimates around 195 or 351. Apparently the true answer is 90, supporting my hypothesis.

Proposal: Maybe use geometric mean instead of arithmetic mean?

I tried to clear my head and try again with geomean:

  • 40 ~ 10,000
  • 40 ~ 632 (ehhh, 159 is more likely to high than too low)
  • 40 ~ 159 (80 is too low)
  • 80 ~ 159 (113)

There's one suspect step around 159, but my guess here is that being anchored by one higher number (632) rather than five (5020, 2530, 1285, 662, 351) is enough to actually make me think "probably less than 159" rather than "no strong opinion about 195". Terminating at 159 also is an outperformance of arithmetic mean, but feels a bit more like luck around where the midpoints fell.

Comment by rossry on Get Rich Real Slowly · 2019-06-12T08:05:54.069Z · score: 3 (2 votes) · LW · GW

What's up with "FDIC insurance up to $1,000,000"? Wikipedia claims that FDIC insurance only covers $0.25mln/bank unless I have a joint account, retirement account, or some kind of legal entity which I'm not.

Comment by rossry on Fractional Reserve Charity · 2019-06-07T12:46:58.638Z · score: 4 (2 votes) · LW · GW

I don't think that there is off-the-shelf insurance for "I lose my job (prospects) or otherwise choose to have lower lifetime earnings, in some way I did not foresee."

It would be confusing to me if most EAs had equity investments they could not afford to bear a crash loss in, especially those involved in an emergency fund scheme. Why add market exposure to the portfolio of donations + scheme membership + liquid cash? (Especially, why as market exposure you expect other scheme participants to share?)

That said, it is possible to buy insurance against a market crash. Probably not as a centralized service.

Comment by rossry on 0.999...=1: Another Rationality Litmus Test · 2019-05-26T22:41:10.149Z · score: 3 (2 votes) · LW · GW

So shouldn't that inequality apply to 0.AAA... (base eleven) and 0.999... (base ten) as well? (A debatable point maybe).

Not debatable, just false. Formally, the fact that for all does not imply that .

If I were to poke a hole in the (proposed) argument that 0.[k 9s]{base 10} < 0.[k As]{base 11} (0.9<0.A; 0.99<0.AA;...), I'd point out that 0.[2*k 9s]{base 10} > 0.[k As]{base 11} (0.99>0.A; 0.9999>0.AA;...), and that this gives the opposite result when you take (in the standard sense of those terms). I won't demonstrate it rigorously here, but the faulty link here (under the standard meanings of real numbers and infinities) is that carrying the inequality through the limit just doesn't create a necessarily-true statement.

0.111...{binary} is 1, basically for the Dedekind cut reason in the OP, which is not base-dependent (or representation-dependent at all) -- you can define and identify real numbers without using Arabic numerals or place value at all, and if you do that, then 0.999...=1 is as clear as not(not(true))=true.

Comment by rossry on No Really, Why Aren't Rationalists Winning? · 2019-05-22T23:09:55.839Z · score: 6 (2 votes) · LW · GW

I think your comment is unnecessarily hedged -- do you think that you'd find much disagreement among LWers who interact with FHI/GMU-Econ over whether people there sometimes (vs never) fail to do level-one things?

I think I understand the connotation of your statement, but it'd be easier to understand if you strengthened "sometimes" to a stronger statement about academia's inadequacy. Certainly the rationality community also sometimes fails to do even the obvious, level-one intelligent character things to enable them to achieve their goals -- what is the actual claim that distinguishes the communities?

Comment by rossry on No Really, Why Aren't Rationalists Winning? · 2019-05-22T12:30:33.702Z · score: 3 (2 votes) · LW · GW

I'm confused; it seems like evidence against the claim that you can get arbitrary amounts of value out of learning generic rationality skills, but I don't see it as "devastating" to the claim you can get significant value, unless you're claiming that "spent years learning all that stuff, and now do it as a day job; some of them 16 hours a day" should imply only a less-than-significant improvement. Or am I missing something here?

Comment by rossry on Counterspells · 2019-04-29T14:30:12.832Z · score: 3 (2 votes) · LW · GW

cf. my comment cousin to this one; I misunderstood what the term was pointing at at first, though I stand by my complaint that that's a problem with the term.

Comment by rossry on Counterspells · 2019-04-28T14:34:51.922Z · score: 3 (3 votes) · LW · GW

Thanks; I legitimately misunderstood at first read whether "counterspell" was intended to apply to the invocations thrown out by bad arguers or the concise and specific distillations the OP is presenting for use. On re-read, I agree that it's supposed to be a set of useful tools.

I remain convinced of the specific claim that "counterspell" is bad jargon (though I don't think it's good practice to cite my own confusion too strongly; the incentives there aren't great). I agree that MtG''s paradigm where more general counterspells are more expensive seems like a good fit for thinking about rhetorical (and perhaps epistemic) tactics, though I reiterate that that's not how they work in many other settings, and that ambiguous baggage is worse than no baggage for this sort of thing. The question of whether identifying counterspells with magic is supposed to be a positive or negative association is additional gratuitous confusion -- I think your claim that the magic metaphor implies they don't work is wrong, but I'm not 85% sure.

Comment by rossry on Counterspells · 2019-04-28T04:40:42.545Z · score: 16 (9 votes) · LW · GW

Strong approval of the overall goal of the post, but here's a semantic criticism:

In accordance with the Rationalist tradition that requires everything to have a nerdy sci-fi or fantasy name

I parse this as an in-joke (and appreciate it as such), but I do think that regularly minting new jargon that's likely to carry substantial, conflicting(!) contextual baggage (not all of it appropriate[1]) is...a bad norm for an epistemic community to have.

I also think that the deeper tradition of jargon-forging (as Eliezer practiced it) involved names that sounded nerdy, but _not_ sci-fi or fantasy -- _cf._ Knowing About Biases Can Hurt People, which uses "Fully General Counterargument" in much the same way(?) as you're using "Counterspell". "Fully General Counterargument" is slightly more unwieldy, but apart from that is a better piece of jargon -- it's less loaded and by leaning even harder into the implicit snark that winks at the fact that the purported counter- isn't working at all, makes it even more clear that no, this is not a useful thing.

[1] To belabor this point, MtG counterspells are fully general (edit: okay, not **fully** general, and see Slider below), and a reasonable fit for the term as you're using it, but D&D (3.5e, at least) counterspells are based on negating a spell by casting a copy of it, which is not what you mean at all. I don't actually know what "counterspells" are in WoD/Mage, but the risk that they're even further afield from your intention should be another strike against using the already-loaded handle.

Comment by rossry on Open Thread April 2019 · 2019-04-28T04:23:18.363Z · score: 1 (1 votes) · LW · GW
preference "my decisions should be mine" - and many people seems to have it

Fair. I'm not sure how to formalize this, though -- to my intuition it seems confused in roughly the same way that the concept of free will is confused. Do you have a way to formalize what this means?

(In the absence of a compelling deconfusion of what this goal means, I'd be wary of hacking epistemics in defense of it.)

There are "friends" who claim to have the same goals as me, but later turns out that they have hidden motives.

Agreed and agreed that there's a benefit to removing their affordance to exploit you. That said, why does this deserve more attention than the inverse case (there are parties you do not trust who later turn out to have benign motives)?

Comment by rossry on Open Thread April 2019 · 2019-04-27T02:57:39.037Z · score: 3 (2 votes) · LW · GW

"give the power over my final decisions to small random events around me" seems like a slightly confused concept if your preferences are truly indifferent. Can you say more about why you see that as a problem?

The potential adversary seems like a more straightforward problem, though one exciting possibility is that lightness of decisions lets a potential cooperator manipulate your decisions on favor of your common interests. And presumably you already have some system for filtering acquaintances into adversaries and cooperators. Is the concern that your filtering is faulty, or something else?

[Commitment] eventually often turn to be winning strategy, compared to the flexible strategy of constant updating expected utility.

Some real-world games are reducible to the game of Chicken. Commitment is often a winning strategy in them. Though I'm not certain that it's a commitment to a particular set of beliefs about utility so much as a more-complex decision theory which sits between utility beliefs and actions.

In summary, if the acquaintances whose info you update on are sufficiently unaligned with you and your decision theory always selects the addition that your posterior assigns the highest utility, then your actions will be "over-updating on the evidence" if your beliefs are properly Bayesian. But I don't think the best response is to bias yourself towards under-updating.

Comment by rossry on Moral Weight Doesn't Accrue Linearly · 2019-04-23T23:22:08.456Z · score: 3 (2 votes) · LW · GW

Do you bite the bullet that this means the set of things you morally value changes discontinuously and predictably as things move out of your light cone? (Or is there some way you value things less as they are less "in" your light cone, in some nonbinary way?)

Comment by rossry on On the Nature of Programming Languages · 2019-04-23T23:15:02.894Z · score: 4 (3 votes) · LW · GW

I think it's from SICP that programs are meant to be read by humans and only incidentally for computers to execute; I've been trying for more than a year now to write a blog post about the fundamental premise that, effort-weighted, we almost never write new programs from scratch, and mostly are engaged in transmuting one working program into another working program. Programs are not only meant to be read by humans, but edited by humans.

I think if you start from the question of how much effort it is to write a new program on a blank page, most languages will come out looking the same, and the differences will look like psychological constructs. If you ask, however, how much effort it is to change an existing piece of a code base to a specific something else, you start to see differences in epistemic structure, where it matters how many of the possible mutations that a human algorithm might try will non-obviously make the resulting program do something unexpected. And that, as you point out, opens the door to at least some notion of universality.

Comment by rossry on On the Nature of Programming Languages · 2019-04-23T22:55:11.028Z · score: 3 (2 votes) · LW · GW

C, the most widespread general-purpose programming language, does things that are extremely difficult or impossible in highly abstract languages like Haskell or LISP

Can you give an example? I'm surprised by this claim, but I only have deep familiarity with C of these three. (My primary functional language includes mutable constructs; I don't know how purely functional languages fare without them.)

Comment by rossry on Open Thread April 2019 · 2019-04-09T23:40:27.223Z · score: 1 (1 votes) · LW · GW

I was trying to construct a proof along similar lines, so thank you for beating me to it!

Note that 2 is actually a case of 1, since you can think of the "walls" of the simplex as being bets that the universe offers you (at zero odds).

Comment by rossry on Open Thread April 2019 · 2019-04-09T11:34:57.791Z · score: 1 (1 votes) · LW · GW

(This comment isn't an answer to your question.)

If I'm understanding properly, you're trying to use the set of bets offered as evidence to infer the common beliefs of the market that's offering them. Yet from a Bayesian perspective, it seems like you're assigning P( X offers bet B | bet B has positive expectation ) = 0. While that's literally the statement of the Efficient Markets Hypothesis, presumably you -- as a Bayesian -- don't actually believe the probability to be literally 0.

Getting this right and generalizing a bit (presumably, you think that P( X offers B | B has expectation +epsilon ) < P( X offers B | B has expectation +BIG_E )), should make the market evidence more informative (and cases of arbitrage less divide-by-zero, break-your-math confusing).

Comment by rossry on Open Thread April 2019 · 2019-04-09T09:46:50.312Z · score: 1 (1 votes) · LW · GW

I'm confused what the word "fairly" means in this sentence.

Do you mean that they make a zero-expected-value bet, e.g., 1:1 odds for a fair coin? (Then "fairly" is too strong; non-degenerate odds (i.e., not zero on either side) is the actual required condition.)

Do you mean that they bet without fraud, such that one will get a positive payout in one outcome and the other will in the other? (Then I think "fairly" is redundant, because I would say they haven't actually bet on the outcome of the coin if the payouts don't correspond to coin outcomes.)

Comment by rossry on How can we respond to info-cascades? [Info-cascade series] · 2019-03-17T01:53:12.102Z · score: 3 (2 votes) · LW · GW

A related idea in non-punishment of "wrong" reports that have insufficient support (again in the common-prior/private-info setting) comes from this paper [pdf] (presented at the same conference), which suggests collecting reports from all agents and assigning rewards/punishments by assuming that agents' reports represent their private signal, computing their posterior, and scoring this assumed posterior. Under the model assumptions, this makes it an optimal strategy for agents to truly reveal their private signal to the mechanism, while allowing the mechanism to collect non-cascaded base data to make a decision.

In general, I feel like the academic literature on market design / mechanism design has a lot to say about questions of this flavor.

Comment by rossry on How can we respond to info-cascades? [Info-cascade series] · 2019-03-17T01:34:53.337Z · score: 10 (3 votes) · LW · GW

Abstract: Considering information cascades (both upwards and downwards) as a problem of incentives, better incentive design holds some promise. This academic paper suggests a model in which making truth-finding rewards contingent on reaching a certain number of votes prevents down-cascades, and where an informed (self-interested) choice of payout odds and threshold can also prevent up-cascades in the limit of a large population of predictors.

1) cf. avturchin from the question about distribution across fields, pointing out that up-cascades and down-cascades are both relevant concerns, in many contexts.

2) Consider information cascades as related to a problem of incentives -- in the comments of the Johnichols post referenced in the formalization question, multiple commentators point out that the model fails if agents seek to express their marginal opinion, rather than their true (posterior) belief. But incentives to be right do need to be built into a system that you're trying to pump energy into, so the question remains of whether a different incentive structure could do better, while still encouraging truth-finding.

3) Up-Cascaded Wisdom of the Crowd (Cong and Xiao, working paper) considers the information-aggregation problem in terms of incentives, and consider the incentives at play in an all-or-nothing crowdfunding model, like venture capital or Kickstarter (assuming that a 'no' vote is irrevocable like a 'yes' vote is) -- 'yes' voters win if there is a critical mass of other 'yes' voters and the proposition resolves to 'yes'; they lose if there is a critical mass and the proposition resolves to 'no'; they have 0 loss/gain if 'yes' doesn't reach a critical mass; 'no' voters are merely abstaining from voting 'yes'.

Their main result is that if the payment of incentives is conditioned on the proposition gaining a fixed number of 'yes' votes, a population of symmetric, common-prior/private-info agents will avoid down-cascades, as a single 'yes' vote that breaks a down-cascade will not be penalized for being wrong unless some later agent intentionally votes 'yes' to put the vote over the 'yes' threshold. (An agent i with negative private info still should vote no, because if a later agent i' puts the vote over the 'yes' threshold based in part on i's false vote, then i expects to lose on the truth-evaluation, since they've backed 'yes' but believe 'no'.)

A further result from the same paper is that if the actor posing the proposition can set the payout odds and the threshold in response to the common prior and known info-distribution, then a proposition-poser attempting to minimize down-cascades (perhaps because they will cast the first 'yes' vote, and so can only hope to win if the vote resolves to 'yes') will be incentivized to set odds and a threshold that coincidentally minimize the chance of up-cascades. In the large-population limit, the number of cascades under such an incentive design goes to 0.

4) I suspect (but will not here prove) that augmenting Cong and Xiao's all-or-nothing "crowdfunding for 'yes'" design with a parallel "crowdfunding for 'no'" design -- i.e., 'no' voters win (resp. lose) iff there is a critical mass of 'no' voters and the proposition resolves 'no' (resp. 'yes') -- can further strengthen the defenses against up-cascades (by making it possible to cast a more informed 'no' vote conditioned on a later, more-informed agent deciding to put 'no' over the threshold).

Comment by rossry on How can we respond to info-cascades? [Info-cascade series] · 2019-03-17T01:30:21.056Z · score: 0 (0 votes) · LW · GW

[this answer was duplicated when I mistakenly copied my comment into an answer and then moved the comment to an answer.]

Comment by rossry on Distribution of info-cascades across fields? [Info-cascade series] · 2019-03-17T00:14:15.158Z · score: 1 (1 votes) · LW · GW

Why stop at 2? Belief-space is large, and many issues admit more than one (+/-) bit of information to cascade.

Comment by rossry on Open Thread February 2019 · 2019-03-02T02:03:26.197Z · score: 1 (1 votes) · LW · GW

But how make small changes in the trajectory of a star? One idea is to impact the star with large comets. It is not difficult, as remote Oort cloud objects (or wandering small planets, as they are not part of already established orbital movement of the star) need only small perturbations to start falling down on the central star, which could be done via nuclear explosions or smaller impacts by smaller astreoids.

I don't think this works; conservation of momentum means that the impact is almost fully counteracted by the gravitational pull that accelerated the comet to such speed (so that, in the end, the delta-v imparted to the star is precisely what you imparted with your nuclear explosions or smaller asteroids).

Maybe a Shkadov thruster is what you want? (It's slow going, though; this article suggests 60ly/200My, accounting for acceleration.)

Comment by rossry on Blackmail · 2019-02-23T10:35:22.371Z · score: 1 (1 votes) · LW · GW

Winner's Curse doesn't seem like the right effect to me -- it seems more like an orthogonality/Goodhart effect, where optimizing for outrageousness decreases the fitness w/r/t social welfare (on the margin). It's always in the blackmailer's interest to make the outrageousness greater, so they're not (selfishly) sad when they overshoot.

Comment by rossry on Can We Place Trust in Post-AGI Forecasting Evaluations? · 2019-02-19T02:11:42.887Z · score: 8 (4 votes) · LW · GW

I'm still thinking about what quantitative estimates I'd stand behind. I think I'd believe that a prize-based competitive prediction system with all eval deferred until and conditioned on AGI is <4% to add more than $1mln of value to [just pay some smart participants for their best-efforts opinions].

(If I thought harder about corner-cases, I think I could come up with a stronger statement.)

Comment by rossry on Can We Place Trust in Post-AGI Forecasting Evaluations? · 2019-02-18T23:39:13.713Z · score: 3 (3 votes) · LW · GW

If the reason your questions won't resolve is that you are dead or that none of your money at all will be useful, I think things are a bit different.

I'm confused; to restate the above, I think that a p% chance that your predictions don't matter (for any reason: game rained out, you're dead, your money isn't useful) is (to first order) equivalent to a p% tax on investment in making better predictions. What do you think is different?

one major ask is that the forecasters believe the AGI will happen in between, which seems to me like an even bigger issue

Sure, that's an issue, but I think that requiring participants to all assume short AGI timelines is tractable in a way that the delayed/improbable resolution issues are not.

I can imagine a market without resolution issues that assumes participants all believe short AGI timelines could support 12 semi-professional traders subsidized by interested stakeholders. I don't believe that a market with resolution issues as above can elicit serious investment in getting its answers right from half that many. (I recognize that I'm eliding my definition of "serious investment" here.)

Comment by rossry on Can We Place Trust in Post-AGI Forecasting Evaluations? · 2019-02-18T14:39:01.178Z · score: 3 (3 votes) · LW · GW

I understand Zvi's points as being relatively universal to systems where you want to use rewards to incentivize participants to work hard to get good answers.

No matter how the payouts work, a p% chance that your questions don't resolve is (to first order) equivalent to a p% tax on investment in making better predictions, and a years-long tie-up kills iterative growth and selection/amplification cycles as well limiting the return-on-investment-in-general-prediction-skill to a one-shot game. I don't think these issues go away if you reward predictions differently, since they're general features of the relation between the up-front investment in making better predictions and the to-come potential reward for doing so well.

(A counterpoint I'll entertain is Zvi's caveat to "quick resolution" -- which also caveats "probable resolution" -- that sufficient liquidity can substitute for resolution. But bootstrapping that liquidity itself seems like a Hard Problem, so I'd need to further be convinced that it's tractable here.)

Comment by rossry on Can We Place Trust in Post-AGI Forecasting Evaluations? · 2019-02-18T13:15:17.761Z · score: 2 (4 votes) · LW · GW

Assuming that your AI timelines are well-approximated by "likely more than three years", Zvi's post on prediction market desiderata suggests that post-AGI evaluation is pretty dead-on-arrival for creating liquid prediction markets. Even laying aside the conditional-on-AGI dimension, the failures of "quick resolution" (years) and "probable resolution" (~20%, by your numbers) are crippling for the prospect of professionals or experts investing serious resources in making profitable predictions.

Comment by rossry on Probability space has 2 metrics · 2019-02-11T06:23:16.236Z · score: 8 (4 votes) · LW · GW

The speculative proposition that humans might only be using one metric rings true and is compellingly presented.

However, I feel a bit clickbaited by the title, which (to me) implies that probability-space has only two metrics (which isn't true, as the later proposition depends on). Maybe consider changing it to "Probability space has multiple metrics", to avoid confusion?

Comment by rossry on Open Thread February 2019 · 2019-02-08T13:23:33.873Z · score: 9 (5 votes) · LW · GW

It varies a lot between papers (in my experience) and between fields (I imagine), but several hours for a deep reading doesn't seem out of line. To take an anecdote, I was recently re-reading a paper (of comparable length, though in economics) that I'm planning to present as a guest of a mathematics reading group, and I probably spent 4 hours on the re-read, before starting on my slides and presumably re-re-reading a bunch more.

Grazing over several days (and/or multiple separate readings) is also my usual practice for a close read, fwiw.

Comment by rossry on X-risks are a tragedies of the commons · 2019-02-07T09:29:36.884Z · score: 2 (2 votes) · LW · GW

I acknowledge that there's a distinction, but I fail to see how it's important. When you (shut up and) multiply out the probabilities, the expected personal reward for putting in disproportionate resources is negative, and the personal-welfare-optimizing level of effort is lower than the social-welfare-optimizing level.

Why is it important that that negative expected reward is made up of a positive term plus a large negative term (X-risk defense), instead of a negative term plus a different negative term (overgrazing)?