Data Processing with Mechanical Turk

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Looking at a photo and deciding whether the person depicted is happy, angry or sad may seem like a trivial task for anyone to do. However, differing contexts and other subtle factors make it very costly for a computer to do the same. Being able to analyze subjective information automatically is an invaluable tool for small businesses. This data can be used to shape business decisions and drive profits. One way to achieve this goal is through crowdsourcing. In other words, getting a large group of volunteers to participate in a common problem and combining their contirbutions. Actually organizing, funding, and managing a project like this can be daunting and expensive, this is where Amazon's Mechanical Turk comes in. This talk explains how Mechanical Turk works and cover various ways in which it can be leveraged by anyone. We will cover use cases that have been successful, the mechanics of posting, processing and testing tasks, and specific tools for accomplishing these goals. This talk was given by Michael Becker and Kelly O'Brien at the 2013 Philly Tech Week on April 23, 2013.

Text of Data Processing with Mechanical Turk

  • processing withmechanical turkKelly OBrien @klm427; Becker @beckerfuffle;

2. Mechanical Turk#ptw2013 3. "The Turk" #ptw2013 4. Lets focus on the crowdsourcing... Relatively cheap means of getting randomsamples of input for small, tedious tasks"Crowdsourced labor can cost companies less than half as much as typical outsourcing" -- Panagiotis G. Ipeirotis, an associate professor at NYUs Stern School of Business#ptw2013 5. "Nothing is a waste of time if you use the experience wisely."~Auguste Rodin #ptw2013 6. The business challenge.... #ptw2013 7. The solution.... #ptw2013 8. Let start with the basicsTemplate DataTemplateTemplate Requesters TemplateData HITsWorkers (Turkers)#ptw2013 9. Use cases Classification Transcription Content Generation Surveys #ptw2013 10. Do people actually use this? #ptw2013 11. AOL#ptw2013 12. Twitter#ptw2013 13. CardMunch @LinkedIn#ptw2013 14. The Sheep Market #ptw2013 15. Development Tools Requester user interface Amazon offers four official APIs Ruby, .NET, Perl, and Java AWS API Boto mturk Python Houdini, Clockwork Raven,Crowdflower, QuikTurKit #ptw2013 16. Create a HIT A title A description Keywords, used to help Workers find the HITs with a search The amount of the reward An amount of time in which the Worker must complete the HIT An amount of time after which the HIT will no longer be availableto Workers The number of Workers needed to submit results for the HITbefore the HIT is considered complete Qualification requirements All of the information required to answer the question#ptw2013 17. Process Results Assignment id Worker id HIT id Assignment status Auto approval time Accept time Submit time Approval time Rejection time Deadline Answer Requester feedback #ptw2013 18. What was the question? Question forms External questions HTML questions #ptw2013 19. Formatting HITs Compact Coherent Cost-effective #ptw2013 20. Bad Actors"Unfortunately, since manually verifying the quality of the submitted results is hard, malicious workers often take advantage of the verification difficulty and submit answers of low quality." [1]#ptw2013 21. Quality Control Manually spotcheck Qualifications Multiple agreement Gold HITs Calculate workererror #ptw2013 22. Quality Control: Manually CheckLook through the results of some workers and manuallyreject/ban those which look bad#ptw2013 23. Quality Control: Multiple Agreement1. Submit HITs to multiple turks (3-10)2. Reject/throw out all HITs below some agreement threshold#ptw2013 24. Quality Control: Qualifications Pay extra for "superior" turksBuild your own custom qualification"Thought Masters was just bad for non-blessed workers? Its even worse for requesters [1]" #ptw2013 25. Quality Control: Gold HITs1. Give turks HITs which we know the correct answer to2. Reject/Ban turks with high error ratesThis technique is used by CrowdFlower #ptw2013 26. Quality Control: Calculate ErrorCalculate each workers error rate based solely on their agreement with otherworkers. Use an expectation-maximization algorithm as described by Dawidand Skene.Lots of math, consider using 3rd party service like Project Troia#ptw2013 27. Auto-approval"Quick approval is important, too. Watching that money pile up is a seriousmotivator; Ill sometimes choose a lower-paying task that approves in close to real time over a higher-paying one that wont pay out for several days."-worker[1]#ptw2013 28. Turkopticon"Turkopticon lets you REPORT and AVOID shadyemployers"#ptw2013 29. Turkernation"If you want to make a living on AmazonMechanical Turk, this is the forum for you"#ptw2013 30. Dos and Donts#ptw2013 31. What exactly do I do with this?#ptw2013 32. A demo in python #ptw2013 33. Requirements #ptw2013 34. Data Details #ptw2013 35. Question template#ptw2013 36. Build a custom qualification #ptw2013 37. Post HITs....#ptw2013 38. Success. #ptw2013 39. Let the work begin.#ptw2013 40. To get results...#ptw2013 41. AWeber Were hiring. 42. ....and we have slides.