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Emerging Technology from the arXiv

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Data Mining Reddit Posts Reveals How to Ask For a Favor, and Get It

There’s a secret to asking strangers for something and getting it. Now data scientists say they’ve discovered it by studying successful requests on the Web.

  • May 23, 2014

One of the more extraordinary phenomena on the Internet is the rise of altruism and of websites designed to enable it. The Random Acts of Pizza section of the Reddit website is a good example.

People leave messages asking for pizza which others fulfill if they find the story compelling. As the site says: “because … who doesn’t like helping out a stranger? The purpose is to have fun, eat pizza and help each other out. Together, we aim to restore faith in humanity, one slice at a time.”

A request might go something like this: “It’s been a long time since my mother and I have had proper food. I’ve been struggling to find any kind of work so I can supplement my mom’s social security … A real pizza would certainly lift our spirits.” Anybody can then fulfill the order which is then marked on the site with a badge saying “got pizza’d,” often with notes of thanks.

That raises an interesting question. What kinds of requests are most successful in getting a response? Today, we get an answer thanks to the work of Tim Althoff at Stanford University and a couple of pals who lift the veil on the previously murky question of how to ask for a favor—and receive it.

Their approach is straightforward. They analyze requests on the Random Acts of Pizza site and look for features that successful ones have on common.

They begin by downloading the entire history of the site from December 2010 to September 2013. This is more than 21,000 posts, which includes requests, fulfillment notes, and other posts.

They then looked at each person who had posted on the site and downloaded their entire history of posts across the whole of Reddit. That added up to a total of 1.87 million posts.

Finally, they filtered out requests where it was unclear whether they had been fulfilled, leaving a total of 5,738 requests. Of these, they were able to identify the benefactor in 379 cases.

They analyzed how various features might be responsible for the success of a post, such as the politeness of the post; its sentiment, whether positive or negative, for example; its length. The team also looked at the similarity of the requester to the benefactor; and also the status of the requester.

Finally, they examined whether the post contained evidence of need in the form of a narrative that described why the requester needed free pizza.

Althoff and co used a standard machine learning algorithm to comb through all the possible correlations in 70 percent of the data, which they used for training. Having found various correlations, they tested to see whether this had predictive power in the remaining 30 percent of the data. In other words, can their algorithm predict whether a previously unseen request will be successful or not?

It turns out that their algorithm makes a successful prediction about 70 percent of the time. That’s far from perfect but much better than random guessing which is right only half the time.

So what kinds of factors are important? Narrative is a key part of many of the posts, so Althoff and co spent some time categorizing the types of stories people use.

They divided the narratives into five types, those that mention: money; a job; being a student; family; and a final group that includes mentions of friends, being drunk, celebrating and so on, which Althoff and co call “craving.”

Of these, narratives about jobs, family, and money increase the probability of success. Student narratives have no effect while craving narratives significantly reduce the chances of success. In other words, narratives that communicate a need are more successful than those that do not.

“We find that clearly communicating need through the narrative is essential,” say Althoff and co. And evidence of reciprocation helps too.

(Given these narrative requirements, it is not surprising that longer requests tend to be more successful than short ones.)

So for example, the following request was successful because it clearly demonstrates both need and evidence of reciprocation.

“My gf and I have hit some hard times with her losing her job and then unemployment as well for being physically unable to perform her job due to various hand injuries as a server in a restaurant. She is currently petitioning to have unemployment reinstated due to medical reasons for being unable to perform her job, but until then things are really tight and ANYTHING would help us out right now.

I’ve been both a giver and receiver in RAOP before and would certainly return the favor again when I am able to reciprocate. It took everything we have to pay rent today and some food would go a long ways towards making our next couple of days go by much better with some food.”

By contrast, the “craving” narrative below demonstrates neither and was not successful.

“My friend is coming in town for the weekend and my friends and i are so excited because we haven’t seen him since junior high. we are going to a high school football game then to the dollar theater after and it would be so nice if someone fed us before we embarked :)”

Althoff and co also say that the status of the requester is an important factor, too. “We find that Reddit users with higher status overall (higher karma) or higher status within the subcommunity (previous posts) are significantly more likely to receive help,” they say.

But surprisingly, being polite does not help (except by offering thanks).

That’s interesting work. Until now, psychologists have never understood the factors that make requests successful, largely because it has always been difficult to separate the influence of the request from what is being requested.

The key here is that everybody making requests in this study wants the same thing—pizza. In one swoop, this makes the data significantly easier to tease apart.

An important line of future work will be in using his work to understand altruistic behavior in other communities, too.

The take-home message here is that if you want free pizza, it helps if you really need one, that you’re willing to pay it back in future, and above all that you can turn all that into a good story.

Good luck!

Ref: http://arxiv.org/abs/1405.3282 : How to Ask for a Favor: A Case Study on the Success of Altruistic Requests

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