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Experimenting On Mechanical Turk
itwbennett writes "In a recent article, Dr. Markus Jakobsson, a Principal Scientist at PARC, offers some tips on effectively running human-subject research studies on Amazon's Mechanical Turk. '...[B]enefits [include] very low experiment costs, quick turn-around rates, and relatively simple approvals from human subjects boards. But you have to be careful to avoid bias and error.' says Dr. Jakobsson. For example, in many situations subjects may be biased just from knowing that they are participating in a study, or by knowing the goals of a study. To avoid this bias, you need to 'convey a different task to your subject than what you are observing — essentially deceive them — to see how they react when faced with the situation of interest. Consider a study of user reactions to phishing sites. You may, for example, say that you are studying the common reaction to online e-commerce sites, and ask them to rate how helpful various sites are, with a free-text input field where they can add other observations. You first show them three or four legitimate websites, asking them to rate and describe them; then you show them a phishing site and do the same. Will they tell you that this is a site run by fraudsters? If they do, they noticed signs of fraud without you prompting them.'" The author also gives tips on avoiding cheaters, and determining how much to pay and when.
For mechanical turkish delight.
Sent from my PDP-11
The title makes it sounds so exciting, like we're experimenting with our robotic Turks.
But the statistician within me is also fascinated with this. It always made me wonder, as the human mind can precondition itself. The study about whether or not prayer helps the sickly followed this mindset, and since the sick humans had no idea what the study was about, when they were told that people were praying for them they thought they were much sicker and actually recovered more slowly. If they hadn't told the sick humans, however, would there have been a large difference?
Math and the brain, it's amazing how they meet.
If I was in a study gauging the helpfulness of various websites and one I was shown a fake website, I would simply assume they ran out of, or could not have access too the real site and so were using a mockup.
If the mockup was particularly bad I might tell them, but otherwise I'd probably chuckle to myself and then just rate it as usual.
There is a huge margin of error with this type of thinking.
Great article, however you should realize it's impossible to completely avoid bias. For example, he has restricted his population to MTurk users while generalizing to the population of web users. He also "weeded out" the lazy people for the convenience of his experiment - aren't there lazy people in the real world?
"Before God we are all equally wise - and equally foolish"
Albert Einstein
The subject basically says it all. If you're conducting a study, either for academia or industry, do yourself a favor and take a good research methods class. I can't count then number of promising studies I've rejected for publication because their methods were poor. While Dr. Jacobson makes some good points, most of them are pretty obvious to anyone who has taken a good class on creating experiments with humans -- for example, deception is a cornerstone of many human studies. Also, for you budding young scientists, make sure you get IRB approval before conducting your study. I reviewed a paper where the authors were clearly from a University and I had questions about the ethics of their methods so I asked for the IRB data for the study...whoops, they never got it. The paper was withdrawn by the authors shortly after.
My Slashdot account is old enough to drink...
When I was a kid, my parents received a free episode of some potential new comedy show to evaluate for them. We watched it, commercials and all. (Yeah, the commercials were a surprise.) At the end, unsurprisingly, the questions were actually about the commercials and only the last was about the show. It didn't fool us at all, of course.
"If you make people think they're thinking, they'll love you; But if you really make them think, they'll hate you." - DM
No, with most people you can do it over, and over, and over.
It's why Fox News makes money.
You are welcome on my lawn.