Monday, July 25, 2011

Native vs Grapevine Reputation on MTurk

The Mechanical Turk blog has a new entry today, by Sharon (Chiarella), titled "Cooking with Sharon" & Tip #3 Manage Your Reputation.

In the article, Sharon encourages requesters to do the following:
  • Pay well - Don’t be fooled into underpaying Workers by comparing your HITs to low priced HITs that aren’t being completed.
  • Pay fairly – Don’t reject an Assignment unless you’re SURE it’s the Worker who is wrong.
  • Pay quickly – If you approve or reject Assignments once a week, Workers may do a few HITs and then wait to see if they are paid before doing more. This is especially true if you’re a new Requester and haven’t established your reputation yet.
Sharon then explains that workers do talk with each other in the forums, on Turkopticon, and so on, and collectively establish the reputation of the requester based on these factors. While there is nothing wrong with this "grapevine"-based reputation, it also illustrates some obvious features that the Mechanical Turk platform is missing.

Instead of outsourcing the task to third-party forums, Amazon should provide features that make the reputation of the requester more transparent, visible, and objective.

For example, each requester could have a profile, in which the workers can see:
  • The total number of HITs, and rewards posted by the requester
  • The rejection rate for the requester
  • The distribution of working time for the HITs of the requester
  • The effective hourly wage for the tasks completed for the requester
  • The payment lag from completion of the task until payment
These are all elements that workers would find useful. They are statistics that contribute to the transparency of the market, and their objective nature makes the establishment of reputation much faster. Such objective characteristics are complementing the more subjective features used in the the grapevine-based reputation systems (Turker Nation, Turkopticon, etc), where only a subset of workers contribute and measure personal perceptions (e.g., was this task "well-paid" or not?). Of course, subjective reputation systems will continue to play their role, providing information that cannot be easily quantified. But they should not be the only reputation signal for the market.

Could there be side-effects if such a system is deployed? Yes. I can see some cases where this profile can introduce strange incentives in the market. (For example, it may be good to have a few of my tasks spammed and still pay immediately for the results, so that I can have high acceptance rate, HITs that require only a little bit of time to be completed, and show a high hourly wage.) But these are just details that can be addressed. There is no way that overall the market could suffer when such statistics become publicly available. (Sorry Mr \$0.23/hr-requester, you are not that valuable.)

Markets operate based on trust and are better with increased information efficiency. Any step towards this direction is a good step for the market participants and, by extension, for the market owner.

Friday, July 22, 2011

A tale about parking

The media attention to my prior blog post was really not something that I enjoyed. Not so much for the attention itself but for focusing on exactly the wrong issues. That post was NOT about me and my evaluation. This is not the main point. I thought that the salary issue was worth mentioning (apparently, it was not) but it was, indeed, a MINOR part of the issue.

In fact, after reflecting on this point, I realized the following: Even if I had received a $1M bonus from NYU for my efforts, the basic problem would still be there: the teaching experience would degenerate into a witch hunt, focusing on cheating, instead of being about learning. And yes, I would still write the same blog post even if I were fully satisfied with my annual evaluation. In fact, the blog post was in my folder of draft posts for a few months now, long before receiving my annual evaluation.

If you want a a parallel, consider this hypothetical story:

A tale about parking

Suppose that you live in a city with a huge traffic problem, and a resulting huge parking problem. Too many cars on the street.

People try to find parking and they drive around, drive around. A lot. Some drivers get frustrated and they double park. Some drivers are stupid enough to double park during rush hour, block the traffic, and leave the car unattended. As expected, the police arrives and assigns a ticket to the offender, sometimes taking the car as well. However, during quiet hours, when there is no traffic many drivers double park, but they do not block the traffic, and nobody gives them a ticket.

Suddenly, in one neighborhood only, call it Redwich Village, a lone policeman starts assigning tickets for every parking violation. No matter if it is minor or major. No matter if the driver just stepped out, or if it is the first time that the driver double parked. Zero-tolerance policy.

By doing that, and being more vigilant, our lone policeman assigns 10 times more tickets that before. By doing that, he also lost countless hours fighting with the offenders. This continuous fight, also annoys some other residents of the neighborhood that want the policeman to focus on policing the neighborhood, and not spend all his time giving parking tickets.

But even our lone policeman gets frustrated: he realizes that he did not become a policeman to give parking tickets. While it is part of his duties, he feels that it is just better not to be so aggressive. His boss also gets a report that many neighborhood residents are annoyed. His boss knows that the complaints are due to the zero-tolerance policy on parking tickets. So he says that he would like our lone policeman to both continue this idiosyncratic zero-tolerance policy enforced just by our lone policeman, and be as diligent with his other duties as before.

Our lone policeman goes on and reflects on the overall experience. He realizes that he is fighting a losing battle. As the number of cars increase in the city, there will be more people parking illegally.

So, our lone policeman suggests that we need to do something more fundamental about the parking problem: He suggests that people could carpool, use bicycles, mass transit, or simply walk. And he asks for people to think of more such alternatives. If there are less cars in the city, the problem will be resolved.

He describes all his thoughts in his blog, in a long post, titled "Why I will never give parking tickets again." He describes the futility of parking tickets to fight the underlying problem, and vows never to be so vigilant about parking tickets. He will be as vigilant as all the other policemen, which is as vigilant as he was before.

His blog post goes viral. Media pick up fragments, everyone reads whatever they want to read. Some headlines:
  • "Parking tickets in Redwich Village increase by 1000%. Is it impossible to park your car in Redwich?"
  • "Parking-related violations skyrocket in Redwich Village. Policeman punished for enforcing the rules."
  • "RedWich Village sucks. Only scumbags live in RedWich Village, what did you expect? Any lawful behavior?"
  • "Stupid city residents: We know that all people that live in cities are cheaters and park illegally"
  • "Why the government does not reward this honest policeman?"
  • "Why this policeman is vowing not to obey the law? Oh the society..."
Now, some of the business owners of Redwich Village are annoyed because people may not drive to Redwich, if they think it is impossible to find parking. Some residents are also annoyed because real estate prices may go down if people believe that Redwich is a place where you cannot park your car. After all, it is all a matter of reputation.

And in this bruhaha, nobody pays any attention to the underlying problem. Is increased vigilance the solution to the parking problem? Should we give more tickets? Should we install cameras? Or should we try to follow the suggestions of our lone policeman and think of other ways to reduce traffic, and therefore resolve the parking problem on a more fundamental level?

The blog post of our lone policeman is neither about the policeman nor about Redwich. It is about the fact that there is too much traffic in the whole city. Which in turn causes the parking problem. Parking scarcity is the symptom, not the real problem. And while he wrote about the traffic problem and suggested solutions, 99% of the coverage was about Rewich and about his own evaluation.

This is exactly how the discussion about cheating evolved in the media. Instead of focusing on how to make student evaluation objective and cheating-proof, the discussion focused on whether my salary went sufficiently up or not. This is not the main point. It is not even a minor point, in reflection. The real question is on how we can best evaluate our students and which evaluation strategies are robust to cheating, encourage creativity, and evaluate true learning.

And this is not a discussion that can be done while screaming.

Sunday, July 17, 2011

Why I will never pursue cheating again

The post is temporarily removed. I will restore it after ensuring that there are no legal liabilities for myself or my employer.

Until then, you can read my commentary in my new blog post: A tale about parking.

The discussion on Hacker News was good as well. Also see the response that I posted at the Business Insider website and the coverage at Inside Higher Education.