Comment by uncomputable on Finance Followups · 2019-01-19T03:58:59.539Z · score: 5 (3 votes) · LW · GW

it's an area where the government could force people to act in their own long-term interest instead of responding to shorter-term incentives

When governments are actively complicit in damaging the financial interests of citizens, it is perverse to legislate fixes before ending the active harm.

And if people want to nitpick exceptions, many exceptions could be written into the law.

In the event legislation like you suggest ever becomes even remotely plausible, please find me, I'd be happy to wager that it'll pass with exceptions for the purchase of government-sponsored lottery tickets.

Comment by uncomputable on How could shares in a megaproject return value to shareholders? · 2019-01-18T19:05:04.068Z · score: 3 (2 votes) · LW · GW

So some organization will still cough up the initial budget, and then some set of potential shareholders will decide that this project will be the first megaproject to run under budget. They'll then give the project more money, in exchange for getting that money back, plus whatever the project doesn't use out of their original budget?

I don't feel like incentives are aligned very well, here.

The organization sponsoring the project is going from the current situation where they can at least lie and pretend that the possibility exists that they'll come in underbudget, to one where they're guaranteed to burn >=100% of the budget if only because they've got to give away the leftovers at the end. In exchange they get maybe a few percent more budget. Do shareholders even get to elect the board of directors?

Middle managers on the project could now easily benefit financially by shorting the equities and sabotaging the project.

Comment by uncomputable on Buy shares in a megaproject · 2019-01-16T17:41:49.891Z · score: 3 (3 votes) · LW · GW

i don't think anything prevents corporations from being created with a limited lifespan, it just doesn't come up.

how are the shares supposed to return value to the share holders?

Comment by uncomputable on Towards no-math, graphical instructions for prediction markets · 2019-01-09T18:49:35.356Z · score: 4 (3 votes) · LW · GW

I remember the tutorials as focusing on easy mode, and treating it as the thing to start with. With Charles refreshing my memory about how easy mode behaved (thank you), I think there was plenty of time for a slow and cautious user to come in and perhaps question the nature of easy mode before they'd done any damage to their account. Certainly I used it a bit at the start, and still recovered nicely.

Hoping that your users will be slow and/or cautious isn't an ideal plan, though.

Comment by uncomputable on Towards no-math, graphical instructions for prediction markets · 2019-01-09T18:39:43.814Z · score: 2 (2 votes) · LW · GW

i'm not sure if it would fix easy mode, but i feel that the points that go into a trade should be some function of the points that have already gone into that question, such that a user's total loss on a given question is capped.

Comment by uncomputable on Towards no-math, graphical instructions for prediction markets · 2019-01-04T21:41:35.458Z · score: 12 (5 votes) · LW · GW

I realized after my initial comment that it was a bit too terse to be productive. Sorry.

(pre-note: Metaculus is not a market, and I don't consider it interesting. I'm addressing and interested only in the case of an actual market where binary securities on events are being traded, with other market participants directly, or all through a market maker like SciCast.)

SciCast had two (major & relevant) modes for placing a trade, I remember them as "easy" and "normal". Normal presented you with a slider from 0% to 100%, you could move the slider back and forth, and as you moved it, you were presented with a continuously updating quote for the "cost" of making the trade. The cost could be negative (equivalent to selling a previously held long position, or closing an existing short position), or positive (going long, or covering a short, whatever). After you made a trade, the interface immediately reflected the percentage that you'd chosen as the new value of the market. While you could go terribly wrong with this interface (and a lot of people did), it was at least possible to do reasonable things.

The Very Bad interface was the "easy" one. Instead of a slider, and instead of being given any feedback about the costs of your trade, you were presented simply with five choices, probably something like <20%, 20-40%, 40-60%, 60-80% and >80%. I don't remember the exact equations that were used at this point, but it caused you to submit a trade that moved the market from wherever it was to as close as it get to the midpoint(?) of the region, without spending more than 1/2 (1/4? something) of your remaining points.

You weren't shown how many points the trade was about to cost you. And neither interface showed you how many points you already had invested in the positions you were adjusting!

About the worst thing (I remember) that happened to naive users (through no fault of their own, IMO) was to come along to a question where the current state of the market was maybe 5%, and then do an easy mode trade for "<20%". The system would spend their points to move the market from 5% to 10%.

The worst thing (which the bad interface encouraged), was users who thought that they should be trading until the market forecast matched their forecast. So if the easy mode trade didn't move the market to where they wanted (or I'd moved the market back in the seconds following their trade), they'd do another easy mode trade. Over and over, with no idea of the position they were building up on a single question.

The short version of the problem, in real-world stock market terms, is: just because you think APPL is only going to go up in the long run doesn't mean that you dump the entirety of your savings into it via market orders.

Think about kelly betting for a minute, just because the user has given you what they believe the odds to be isn't enough to compute the correct bet for them. You also need to know their bankroll. And if you're letting them trade on lots of questions simultaneously, you should be taking in a lot of probability estimates from the user, comparing them all to the state of the market, and making the trades that are profitable: ones where 1) the user believes the market is very wrong and 2) where corrections can be made inexpensively.

(For bonus points the user gives you the conditional probabilities between all those things, too, so that you can avoid betting too much on correlated trades.)

thats, uh, probably enough for now. i'll keep an eye out for any questions.

Comment by uncomputable on Towards no-math, graphical instructions for prediction markets · 2019-01-04T17:29:23.244Z · score: 6 (4 votes) · LW · GW

I made an astonishing pile of points on SciCast from people who did not understand what the simple "user friendly" interface was doing. Turning "what i think the the distribution is" into a single trade is a fraught process; permit the user to do it repeatedly for a given question and I will actually show up and take absolutely all of their money.

Comment by uncomputable on State Machines and the Strange Case of Mutating API · 2018-12-24T17:40:47.400Z · score: 3 (2 votes) · LW · GW

there's been some work on adding linear types to programming languages, to do things like ensure that you can't use a resource after it has been closed/freed. similarly you could prevent the use of a resource before it has been fully opened/configured. (useful for sockets since they require multiple steps.)

wadler's "linear types can change the world!" might be an appropriate starting point.

apologies, i have not read it. linear types are outside my area of interest.

Comment by uncomputable on The Art of the Overbet · 2018-10-19T19:38:40.044Z · score: 16 (5 votes) · LW · GW

if you drop the gambler's presentation of kelly, and just maximize expected log utility, you immediately get the correct answer for the "win or die" scenario. the second scenario lightly touches on kelly, and would also be aided by considering the situation as log utility maximization. (expenses going out every month like clockwork, decision is work (small guaranteed return), and/or how much to allocate to various bets.)

some of your concerns in the last post can also be modeled properly.