Author Archives: ctwardy

About ctwardy

SciCast PI, Research Assistant Professor at George Mason; Cognitive Science, Judgment and Decision Making, Bayesian networks, AI, Causal Inference, Reasoning Under Uncertainty, Philosophy of Science, Bayesian search theory,

New Policy: Aftercasts discarded

Our sponsor has made the sensible request that we discount forecasts after the answers are known — even if it took us awhile to pause the question. We have now instrumented SciCast to record and show ‘Date Known.’  Forecasts after ‘Date Known’ will still be part of the historical record, but they will neither gain nor lose points. Remember to check this during the mandatory 48-hour comment period following a proposed resolution.  (In the future it may be possible to soften the cutoff, or create a fixed bonus for first correct report of a resolution.)

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Boo! Shadow forecasts on SciCast

In time for Hallowe’en, we’ve added Shadow Forecasts and other features to help show the awesome power of combo.

  1. Shadowy: when linked forecasts affect a question, we show “Shadow Forecasts” in the history and the trend graph.legend
  2. Pointy: the trend graph now shows one point per forecast instead of just the nightly snapshot.
  3. Chatty: Comment while you forecast.  (But not while you drive.)

Read on for news about upcoming prizes.

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New Approach to Conditional (Combo) Forecasts…

Tonight’s release streamlines combo trades, adds some per-question rank feedback, prettifies resolutions, and disables recurring edits.

Screen Shot 2014-09-23 at 9.28.27 PM

We’ve redone the approach to trading linked questions. Now if the question is linked to other questions, you can make any desired assumptions right from the main trade screen.

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Scaled Continuous Question

The following shows an example of a Scaled or Continuous question:

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Instead of estimating the chance of a particular outcome, you are asked to forecast the outcome in natural units like $.  Forecasts moving the estimate towards the actual outcome will be rewarded. Those moving it away will be penalized.  As with probability questions, moving toward the extremes is progressively more expensive: we have merely rescaled the usual 0%-100% range and customized the interface.

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Why did my forecast do that?

Forecasters frequently want to know why their forecast had so much (or so little) effect. For example, Topic Leader jessiet recently asked:

I made a prediction just now of 10% and the new probability came down to 10%. That seems weird- that my one vote would count more than all past predictions? I assume it’s not related to the fact that I was the question author?

The quick answer is that she used Power mode, which is our market interface, and that’s how markets work: your estimate becomes the new consensus.  Sound crazy? Note that markets beat out most other methods for the past three years of live geopolitical forecasting on the IARPA ACE competition. For two years, we ran one of those markets, before we switched to Science & Technology.  So how can this possibly work?  Read on for (a) How it works, (b) Why you should start with Safe mode, (c) The scoring rule underneath, and (d) An actual example.

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Comment notifications temporarily disabled

A new SciCast ad campaign has created ~1,000 registrations per day for the past couple of days.  That has doubled our forecaster community and created a lot of activity, which is great.  But it also generated a lot of email notifications for users who had opted to receive updates for new comments, and more email is not always great.

After a dozen or so complaints and a review of some comments, we have disabled email notifications until we add some more controls.

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Second Dicty Amateur Video Analysis (17-May)

** Updated 18-May **

Some videos have been added today (refresh https://scicast.org/dicty), so I took a second look.  I don’t look through microscopes for a living, so this isn’t final.  Times below are the timestamped clock time, which elapses at about 8m per frame. I collected:

  • TeamNum: Team name number stated in the video title
  • TeamName: Team name and/or PI name(s)
  • t_First: time when the first cell entered the finish zone. There is some ambiguity for cells that hang out on the opening.
  • Num_3hr: #cells in the finish zone by the 3hr mark; not sure how Irimia is counting cells that leave after entering
  • Num_5hr: #cells in the finish zone by the 5hr mark (only 4 videos)
  • Notes: salient notes, in quotes

Often there were two mazes and finish lines visible.  In these cases I tried to count both finish lines.  I’m not sure that’s canonical.  Here are the results as I saw them (Changed format to avoid margin clipping; sorted by Num_3hr):

TeamNum,TeamName,t_First,Num_3hr,Num_5hr,Notes
Team 12,Kortholt,1:36,14,,”3 in at 1:36,4 @ 1:40,at least 14 at 3h”
Team 11,Faix,1:28,12,,3 in @ 1:36; I counted at least 12 entering by 3h
Control HL60,,1:42,9,,9+. I can’t get it to hold the last frame to count.
Team 9 HL60,Insall,2:14,5,,5+. Many cells got bored and went back into the maze.
Team 17,Kimmel,1:36,5,,5+. Can’t hold the last frame.
Caffeine Control,,1:56,4,,Last one just in time.
Race2Control,,2:15,2,5,”Lots of cells,lots of movement,esp. outside the maze.”
Racer X Neutrophils,,2:25,2,,Cell entering 2:25 jumps track next frame 2:30. Entered?
Team1,Strassman & Queller,2:38,1.5,3,Video starts at 1:30; 2nd cell just crossing at 3:00
Team 9,Insall,,0,0,”Video starts at 1:30; hard to see,but cells appear disorganized.”
Team18,Kay,4:07,0,1,Cells outside the maze are much faster!
Team5 HL60,Steinckwich-Besancon,,0,,”Only 5-6 cells visible,hardly moving.”
Team 19 HL60,Tschirhart,,0,,17 cells idly drifting around the mazes.
Team 7,Bruce,,0,,Halfway through the maze at 3h.
Team 10,Beta,,0,,No cells visible on the slide.
Team 20,Devreotes,,0,,Only 1 confused cell. Did preliminary videos have the wrong label?
Team 9,Insall,,0,,About halfway through at 3h.
Team 15,Myre,,0,,About halfway through at 3h.
Team14,Muller-Taubenberger,,,,Irimia says cells did not get to the starting line.

So, likely winners:

  • Overall winner (most finishers at 3h): Team 12 (Kortholt) with 14+ cells.  We had an email from Irimia mid-afternoon saying at that point they also thought 12 was the most likely.  Second place is probably Team 11 (Faix) with 12+ cells in. Third is likely to be either the HL60 line from Team 9 (Insall), or Team 17 (Kimmel), both with at least 5 cells in by 3hr.
  • Fastest: Team 11 (Faix) just edges out Teams 12 (Kortholt) and 17 (Kimmel) for the fastest single cell at 1:28. This may turn on the precise definition of finish line.
  • Smartest: Sorry, I don’t have the patience to count wrong turns.

Notes: Neutrophils need to be photographed more often — the fastest ones are simply sprinting too fast to uniquely infer motion between frames.

You can still edit the Fastest and Smartest questions.  Until Irimia announces the winners anyway.   https://scicast.org/dicty.

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Can crowdsourcing help find the missing Malaysia Airlines flight #MH370?

On SciCast, we’ve posted three questions about the missing plane. Can crowdsourcing help to locate it?

Dr. Charles Twardy, Project Principal, explains the different ways to crowdsource a search. “When a community turns out to help look for a lost child, that’s crowdsourcing,” he says. “The community volunteers typically aren’t as well-prepared as the search teams, but when directed by experienced Field Team Leaders, they can greatly extend the search effort. Similarly, experimental micro-tasking sites like TomNod.com let volunteers help search piles of digital images. Call it the effort of the crowd. SciCast is about the wisdom of the crowd: weighing the vast amounts of uncertain and conflicting evidence to arrive at a group judgment, of say the relative chances of several regions or scenarios. This could be as simple as an average – a robust method with much to recommend it when judgments are independent.  Or it could be something more advanced, like SciCast’s combinatorial prediction market.  A market reduces double-counting, and may be better suited to the case where most of us are just mulling over the same information, but a few have real insight. The trick is to find a large and diverse crowd, and persuade them to participate.”

Following are the questions. Click any of them to make your forecast (register or login first). Also, see the discussion and background tabs of each question for more details and links to news sources.

Where will the Malaysia Airlines Flight MH370 be found?

What happened to Malaysia Airlines Flight MH370?

Where will Malaysian Air Flight MH 370 be found (extended version)?

The extended search region uses this map.

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See this blog post for info on how to explore conditional probabilities.

Click here to read more about approaches to crowdsourcing Search & Rescue.

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