ASA 2014 Hackathon – Are you in?

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UPDATE 2013-10-01: Nate Porter pointed out that the Hacker League page doesn’t let you sign up. For now, use this Google doc.

A lot of folks on Twitter during ASA this year were chatting about the possibility of a hackathon during ASA 2014 in San Francisco. The reasons for having a hackathon, I think, are myriad; here are some of the various “purposes” that myself and members of the computational sociology listserv have considered:

  • Incorporate computational methods into social science through teh h4x
  • Inspire participants to apply computational methods to common social science problems
  • Create an organizational nexus for computational sociology which makes it a vibrant and visible part of the discipline
  • Develop and foster social ties that strengthen the field and point to the value of non-traditional venues for collaboration
  • Create useful and interesting research products.
  • Solidify connections among sub-community of folks in/around sociology who have a set of skills/tools/interests in things computational
  • Increase visibility of that sub-community, partly by showcasing what can be done
  • To support claim that sociology has a role to play in computational social science and that computation has a role to play in sociology.
  • Connect folks already immersed in these skill areas with folks who are around the edges, curious, etc.
  • To actually impart some new skills/ideas to folks.
  • To actually produce something collectively useful.
  • To lay foundation for something that could grow in future years at ASA meetings or in ASA in general (e.g., a network of folks working with these tools).

I’m really excited about the prospect of this. Laura Norén, Christopher Weiss, and I have been plotting to make this thing a reality. Right now we’re trying to gauge how many people would come out to such an event.

If you have even a tiny inkling that you might come to the hackathon, sign up at the Hacker League page.

International Summer School on Social Network Analysis: Introduction and Methods of Analysis in R

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As mentioned in a previous post, Alex Hanna and I had the opportunity to teach last week at the Higher School of Economic’s International Social Network Analysis Summer School in St. Petersburg.  While last year’s workshop emphasized smaller social networks, this year’s workshop focused on online networks.  For my part, I provided an introductory lecture to social network analysis along with four labs on the subject of R and social network analysis.

The introduction to social network analysis began with an historical overview, followed by outlining which concepts constitute a social network.  The remaining portions review subjects relating to subgraphs, walks, centrality, cohesive subgroups, along with major research subjects in the field.  Setting aside the substantive interest in networks, the first lab covered basic R usage, objects, and syntax.   Admittedly, this material was relatively dryer, though necessary to make the most of the network analysis software in R.  We followed this introduction to R with an introduction to R’s social network analysis software.  This second lab introduces the class to the different network packages within R, reading data, basic measurements brought up in the introductory lecture, and visualization.  The third R SNA lab was on the subject of graph-level indices, random graphs, and Conditional Uniform Graph tests.  Both the second and third labs were conducted primarily using the igraph package.  The fourth and final lab of the course was on the subject of exponential random graph modeling.  For this lab, we walked through tests for homophily and edgewise-shared partner effects using data on both our Twitter hashtag (#SNASPb2013) as well as US political blogs.

The slides include scripts that download and read the data used within all lab examples.

I’ve hosted PDFs of all the slides on Google Drive.

Network data collection workshops from SNA Summer School

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Benjamin Lind and I have spent the last week and a half teaching at the Social Network Analysis Summer School at HSE-St. Petersburg. We’ve had about 30 students coming from as far as South Africa and Sweden, with all levels of skill and many different research interests, and have had the pleasure of teaching with some great instructors from around the world as well. If you are getting inquisitive for more info – keep reading, it gets exciting. You can read the backchannel chatter the #SNASPb2013 hashtag

I ran two labs on collecting network data from various Internet sources with Python. The first is a mashup of some of my prior workshops on collecting Twitter data via the API, and drawing network data through user mentions. The second shows how to retrieve network data by crawling blogs.

Technology-wise, it was my first time using a cloud service (Amazon EC2) and iPython Notebooks for teaching purposes. A few observations into EC2 for teaching: the t1.micro server level is not quite powerful enough to handle ~30 students running parsing of JSON or scrapy. So you’ll have to up the juice, otherwise. I found iPython Notebooks to be great, though — code highlighting and execution, LaTeX typesetting, and Markdown makes it a winner in my book.

I also put the code for each lab on GitHub: hse-twitter and hse-scrapy. Would love any contributions to these small scripts, especially the scraping code.

Computational sociology panels at #asa13

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The ASA annual meeting starts on Friday, and the program is about 200 pages long. But don’t worry, we’ve got you covered. Here’s a few computational sociology events that you should catch, suggested by folks on the computational sociology listserv.

If you know of any more that look interesting, feel free to post them in the comments and I’ll add them to this Google Calendar.

Awesome food in NYC for #asa13

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Seeing Shamus Khan and Phil Kasinitz’s ASA eating guide, I asked a colleague and friend of mine, Grace Nguyen, (a former chef and sometimes New Yorker) to put together a list of good, cheap(er) food options for NYC in preparation for this year’s ASA.
Here’s her compilation. A few more suggestions from her may be forthcoming in the comments. The places are linked to their Yelp pages.
You should also hit up some of these places after the Bad Hessian party, since you’ll be in the Village anyhow.

Spatial Playtime

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There have been repeated calls for “space” in many fields of social science (all links are behind paywalls, sorry):

  • Demography: (Voss 2007)
  • Sociology: (Gieryn 2000)
  • Epidemiology: for an early critical review (Jacquez 2000)
  • Geography: obviously geographers were into space before it was cool. A couple of pieces I like are Doreen Massey’s book, For Space and O’Sullivan (2006) for a review of GIS.
  • Anthropology: the proceedings of a conference including a piece by Clifford Geertz, Senses of Place (1996). Though what I’m writing here has less to do with the space/place debate.

These are nice papers about what the authors think should be new research agendas, bu I think social sciences need to stop calling for space and start “playing” with space. Let me explain…

This idea started when fellow Bad Hessian, Alex Hanna, suggested that I read a paper about spatio-temporal models of crime in Chicago. We are in the same writing group. Alex has suffered through many presentations of a paper I’m writing about crime in Chicago. Chicago? Crime? I mean these have to be related papers, right? So I gave it a quick read:

Seth R. Flaxman, Daniel B. Neill, Alex J. Smola. 2013. Correlates of homicide: New space/time interaction tests for spatiotemporal point processes. Heinz College working paper, available at: http://www.heinz.cmu.edu/faculty-and-research/research/research-details/index.aspx?rid=483

…and it’s a really great paper! Flaxman reviews three standard measures for spatial and temporal independence and then proposes a new measure that can simultaneously test for spatio-temporal dependence. The measures are validated against real crime data from Chicago. On the other hand, it’s also completely useless for my project. I mean, I stuck it in a footnote, but I can’t engage with it in a substantively meaningful way because my paper is about the Modifiable Areal Unit Problem and the good ol’ MAUP is fundamentally about polygons — not points. The MAUP occurs because a given set of points can be aggregated into any number of different polygon units, and the subsequent results of models, bivariate relationships, or even hot spot analysis might change based on the aggregation method.

This means that Flaxman’s approach and my approach are not comparable because they each rest on different assumptions about how to measure distance, social interaction, and spatial dependence. They’re based on different spatial ontologies, if you will. But back to the main argument of this post: could we play around with the models in Flaxman, the models I’m making, plus some other models in order to test some of the implications of our ideas of space? Here are some hypothetical hypotheses….

Isotropy. Isotropy means that effects are the same in every direction. For example, weather models often take into account anisotropy because of prevailing wind direction. As Flaxman mentions at the end of the paper, alternative distance measures like Manahatten distance could be used. I would take it a step further and suggest that distance could be measured across a trend surface which might control for higher crime rates on the south side of Chicago and in the near-west suburbs. Likewise, spatial regression models of polygon data can use polynomial terms to approximate trend surfaces. Do the additional controls for anisotropy improve model fit? Or change parameter estimates?

Spatial discontinuities. A neighborhood model posits — albeit implicitly and sort of wishy-washy — that there could be two locations that are very close as the crow flies, but are subject to dramatically different forces because they are in different polygons. These sharp breaks might really exist, e.g. “the bad side of the tracks”, red-lining, TIFF funding, empowerment zones, rivers, gated suburbs. Or they might not. Point process models usually assume that space is continuous, i.e. that there are no discontinuities. Playing around with alternative models might give us evidence one way or another.

Effect decay. In spatial regression models like I’m using, it’s pretty normal to operationalize spatial effects for contiguous polygons and then set the effect to zero for all higher order neighbors. As in the Flaxman paper, most point models use some sort of kernal function to create effect estimates between points within a given bandwidth. These are both pretty arbitrary choices that make spatial effects too “circular”. For exmple, think of the economic geographies of interstate exchanges in middle America. You’ll see fast food, big box retail, gas stations, car dealerships, hotesls, etc. at alomst every interchange. Certainly there is a spatial pattern here but it’s not circular and it’s not (exponentially, geometrically, or linearly) decaying across distance. Comparisons between our standard models — where decay is constrained to follow parametric forms — and semi-parametric “hot spot” analyses might tell us if our models of spatial effects are too far away from reality.

Ok. Those sound like valid research questions, so why not just do that research and publish some results? As I see it, spatial work in social sciences usually boils down to two main types of writing. First, there are the papers that aren’t terribly interested in the substantive research areas, and are more about developing statistical models or testing a bunch of different models with the same data. Here are some examples of that type:

  • (Dormann et al 2007) undertake a herculean task by explicating and producing R code for no less than 13 different spatial models.
  • (Hubbard et al 2010) compare GEE to mixed models of neighborhood health outcomes.
  • (Tita and Greenbaum 2009) compare a spatial versus a spatio-social network as weighting matrices in spatial regression.

The problem with this approach is that the data is often old, simplified data from well-known example datasets. Or worst yet, it is simulated data with none of the usual problems of missing data, measurement error, and outliers. At best, these papers use over simplified models. For example, there aren’t any control variables for crime even when there is a giant body of literature about the socio-cultural correlates of spatial crime patterns (Flaxman and I are both guilty of this).

The second type of research would be just the opposite: interested in the substantive conclusions and disinterested in the vagaries of spatial models. They might compare hierchical or logistic regressions to the spatial regressions, but very rarely go in depth about all the possible ways of operationalizing the spatial processes they’re studying. And when you think about it, you can’t blame them because journal editors like to see logical arguments for the model assumptions used in a paper – not an admission that we don’t know anything about the process under study and a bunch of different models all with slightly different operationalizations of the spatial process. But here’s the thing: we don’t actually know very much about the spatial processes at work! And we have absolutely no evidence that the spatial processes for, say, crime are also useful in other domains like educational outcomes, voting behavior, factory siting, human pathogens, or communication networks.

Thus, we don’t need more social science papers that do spatial models. We need (many) more social science papers that do multiple, incongruent spatial models on the same substantively rich datasets. I think it’s only by modeling, for example, crime as an isotropic point process, a social network with spatial distance between nodes, and a series of discrete neighborhood polygons can we start to grasp if one set of assumptions about space is more/less accurate and more/less useful. In case you couldn’t tell, I’m a big fan of George Box’s famous quote. This is the slightly longer version:

“Remember that all models are wrong; the practical question is how wrong do they have to be to not be useful.” (Box & Draper 1987, 74)

Good luck, and go play!

[Update, 2013-07-22: I changed the citation to the Flaxman paper, as it is now a working paper in his department at Carneige Mellon University.]

Converting approximating numerical words to numbers?

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I’ve jumped in on the development of the rewrite of TABARI, the automated coding system used to generate GDELT, and the Levant and KEDS projects before it. The new project, PETRARCH, is being spearheaded by the project leader Phil Schrodt and the development led by Friend of Bad Hessian John Beieler. PETRARCH is, hopefully, going to be more modular, written in Python, and have the ability to work in parallel. Oh, and it’s open-source.

One thing that I’ve been working on is the ability to extract features from newswire text that is not related to coding for event type. Right now, I’m working on numerical detection — extracting relevant numbers from the text and, hopefully, tagging it with the type of number that it is. For instance:

One Palestinian was killed on Sunday in the latest Israeli military operation in the Hamas-run Gaza Strip, medics said.

or, more relevant to my research and the current question at hand:

Hundreds of Palestinians in the Gaza Strip protested the upcoming visit of US President George W. Bush on Tuesday while demanding international pressure on Israel to end a months-old siege.

The question is, do any guidelines exist for converting words like “hundreds” (or “dozens”, “scores”, “several”) into numerical values? I’m not sure how similar coding projects in social movements have handled this. John has suggested the ranges used in the Atrocities Event Data (e.g. “several” = 5-24, “tens” = 50-99). What other strategies are there?

Challenges of automated Arabic/Persian transliteration

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Prompted by a tweet yesterday from Ella Wind, an editor at the great Arab commentary site Jadaliyya, I undertook the task of writing a very quick and dirty converter that takes Arabic or Persian text and converts it to the International Journal of Middle East Studies (IJMES) transliteration system (details here [PDF]). I’ve posted the actual converter here. It’s in very initial stages and I will discuss some of the difficulties of making it more robust below.

It’s nice that the IJMES has an agreed upon transliteration system; it makes academic work much more legible and minimizes quarrels about translation (hypothetically). For example, حسني مبارك (Hosni Mubarak) is transliterated as ḥusnī mubārak.

Transliterating, however, is a big pain. The transliterated characters are not in the ASCII character set [A-Za-z0-9] that is mostly used by English and other Western languages, and many of its characters are largely drawn from Unicode (e.g. ḥ). That means a lot of copy-pasta of individual Unicode characters from the character viewers in your OS or some text file that stores them.

When Ella posted the tweet, I thought that programming this would be a piece of cake. How hard would it be to write a character mapping and throw up a PHP interface? Well, it’s not that simple. There are a few problems with this.

1. Most Arabic writing does not include short vowels.

Arabic is a very precise language (I focus the rest of this article on Arabic because I don’t know much about Persian). There are no silent letters and vowels denote verb form and casing. But in most modern Arabic writing, short vowels are not written in because readers are expected to know them. For example, compare the opening of al-Faatiha in the Qu’ran with vowels:

بِسْمِ اللَّهِ الرَّحْمَٰنِ الرَّحِيمِ

to without them:

بسم الله الرحمن الرحيم

In the Qu’ran, all vowels are usually written. But this doesn’t occur in most modern books, signs, and especially newspaper and social media text.

So what does this mean for transliteration? Well, it means that you can’t transliterate words precisely unless the machine knows which word you’re going for. The average Arabic reader will know that بسم should be “bismi” and not “bsm.”

I can suggest two solutions to this problem: either use a robust dictionary that can map words without vowels to their voweled equivalent, or have some kind of rule set that determines which vowels must be inserted into the word. The former seems eminently more plausible than the latter, but even so, given the rules of Arabic grammar, it would be necessary to do some kind of part-of-speech tagging to determine the case endings of words (if you really want to know more about this twisted system, other people have explained this much better than I can). Luckily, most of the time we don’t really care about case endings.

In any case, short vowels are probably the biggest impediment to a fully automated system. The good news is that short vowels are ASCII characters (a, i, u) and can be inserted by the reader.

2. It is not simple to determine whether certain letters (و and ي) should be long vowels or consonants.

The letters و (wāw) and ي (yā’) play double duty in Arabic. Sometimes they are long vowels and sometimes they are consonants. For instance, in حسني (ḥusnī), yā’ is a long vowel. But in سوريا (Syria, or Sūriyā), it is a consonant. There is probably some logic behind when one of these letters is a long vowel and when it is a consonant. But the point is that the logic isn’t immediately obvious.

3. Handling dipthongs, doubled letters, and reoccurring constructions.

Here, I am thinking of the definite article ال (al-), dipthongs like وَ (au), and the shaddah ّ  which doubles letters. This means there probably has to be a look-ahead function to make sure that these are accounted for. Not the hardest thing to code in, but something to look out for nonetheless.

Those are the only things I can think of right now, although I imagine there are more lurking in the shadows that may jump out once one starts working on this. I may continue development on this, at least in an attempt to solve issues 2 and 3. Solving issue 1 is a task that will probably take some more thoughtful consideration.