Text analysis « Bad Hessian

Sadly, we haven’t posted in a while. My own excuse is that I’ve been working a lot on a dissertation chapter. I’m presenting this work at the Young Scholars in Social Movements conference at Notre Dame at the beginning of May and have just finished a rather rough draft of that chapter. The abstract:

Scholars and policy makers recognize the need for better and timelier data about contentious collective action, both the peaceful protests that are understood as part of democracy and the violent events that are threats to it. News media provide the only consistent source of information available outside government intelligence agencies and are thus the focus of all scholarly efforts to improve collective action data. Human coding of news sources is time-consuming and thus can never be timely and is necessarily limited to a small number of sources, a small time interval, or a limited set of protest “issues” as captured by particular keywords. There have been a number of attempts to address this need through machine coding of electronic versions of news media, but approaches so far remain less than optimal. The goal of this paper is to outline the steps needed build, test and validate an open-source system for coding protest events from any electronically available news source using advances from natural language processing and machine learning. Such a system should have the effect of increasing the speed and reducing the labor costs associated with identifying and coding collective actions in news sources, thus increasing the timeliness of protest data and reducing biases due to excessive reliance on too few news sources. The system will also be open, available for replication, and extendable by future social movement researchers, and social and computational scientists.

You can find the chapter at SSRN.

This is very much a work still in progress. There are some tasks which I know immediately need to be done — improving evaluation for the closed-ended coding task, incorporating the open-ended coding, and clarifying the methods. From those of you that do event data work, I would love your feedback. Also if you can think of a witty, Googleable name for the system, I’d love to hear that too.

This is a guest post by Charles Seguin. He is a PhD student in sociology at the University of North Carolina at Chapel Hill.

Sociologists and historians have shown us that national public discourse on lynching underwent a fairly profound transformation during the periods from roughly 1880-1925. My dissertation studies the sources and consequences of this transformation, but in this blog post I’ll just try to sketch some of the contours of this transformation. In my dissertation I use machine learning methods to analyze this discursive transformation, however after reading several hundred lynching articles to train the machine learning algorithms, I think I have a pretty good understanding of key words and phrases that mark the changes in lynching discourse. In this blog post then, I’ll be using basic keyword, bigram (word pair), and trigram searches to illustrate some of the changes in lynching discourse.

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This is a guest post by Laura K. Nelson. She is a doctoral candidate in sociology at the University of California, Berkeley. She is interested in applying automated text analysis techniques to understand how cultures and logics unify political and social movements. Her current research, funded in part by the NSF, examines these cultures and logics via the long-term development of women’s movements in the United States. She can be reached at lknelson3@berkeley.edu.

Computer-assisted, or automated, text analysis is finally making its way into sociology, as evidenced by the new issue of Poetics devoted to one technique, topic modeling (Poetics 41, 2013). While these methods have been widely used and explored in disciplines like computational linguistics, digital humanities, and, importantly, political science, only recently have sociologists paid attention to them. In my short time using automated text analysis methods I have noticed two recurring issues, both which I will address in this post. First, when I’ve presented these methods at conferences, and when I’ve seen others present these methods, the same two questions are inevitably asked and they have indeed come up again in response to this issue (more on this below). If you use these methods, you should have a response. Second, those who are attempting to use these methods often are not aware of the full range of techniques within the automated text analysis umbrella and choose a method based on convenience, not knowledge.

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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?

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.

R users know it can be finicky in its requirements and opaque in its error messages. The beginning R user often then happily discovers that a mailing list for dealing with R problems with a large and active user base, R-help, has existed since 1997. Then, the beginning R user wades into the waters, asks a question, and is promptly torn to shreds for inadequate knowledge of statistics and/or the software, for wanting to do something silly, or for the gravest sin of violating the posting guidelines. The R user slinks away, tail between legs, and attempts to find another source of help. Or so the conventional wisdom goes. Late last year, someone on Twitter (I don’t remember who, let me know if it was you) asked if R-help was getting meaner. I decided to collect some evidence and find out.

Our findings are surprising, but I think I have some simple sociological explanations.
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(GIF via Dilettwat)

We’re down to the final episode. This one is for all the marbles. Wait, that’s not the best saying in this context. In any case, moving right along. In the top four episode, Detox was eliminated, but not after Roxxxy threw maybe ALL of the shade towards Jinkx (although, to Roxxxy’s credit, she says a lot of this was due to editing).

Jinkx, however, defended herself well by absolutely killing the lipsync. Probably one of the top three of the season, easy.

Getting down to the wire, it’s looking incredibly close. As it is, the model has ceased to tell us anything of value. Here are the rankings:

1         Alaska  0.6050052  1.6752789
2 Roxxxy Andrews  2.5749070  3.6076899
3  Jinkx Monsoon  3.4666713  3.2207345

But looking at the confidence intervals, all three estimates are statistically indistinguishable from zero. The remaining girls don’t have sufficient variation on the variables of interest to differentiate them from each other in terms of winning this thing.

So what’s drag race forecaster to do? Well, the first thought that came to my mind was — MOAR DATA. And hunty, there’s one place where I’ve got data by the troves — Twitter.

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This is a guest post by John Beieler, originally posted at http://johnbeieler.org/blog/2013/04/12/gdelt/

I made the remark on Twitter that it seemed like GDELT week due to a Foreign Policy piece about the dataset, Phil and Kalev’s paper for the ISA 2013 meeting, and a host of blog posts about the data. So, in the spirit of GDELT week, I thought I would throw my hat into the ring. But instead of taking the approach of lauding the new age that is approaching for political and social research due to the monstrous scale of the data now available, I thought I would write a little about the issues that come along with dealing with such massive data.

Dealing with GDELT

As someone who has spent the better part of the past 8 months dealing with the GDELT dataset, including writing a little about working with the data, I feel that I have a somewhat unique perspective. The long and the short of my experience is: working with data on this scale is hard. This may strike some as obvious, especially given the cottage industry that has sprung up around Hadoop and and other services for processing data. GDELT is 200+ million events spread across several years. Each year of the reduced data is in a separate file and contains information about many, many different actors. This is part of what makes the data so intriguing and useful, but the data is also unlike data such as the ever-popular MID data in political science that is easily managed in a program like Stata or R. The data requires subsetting, massaging, and aggregating; having so much data can, at some points, become overwhelming. What states do I want to look at? What type of actors? What type of actions? What about substate actors? Oh, what about the dyadic interactions? These questions and more quickly come to the fore when dealing with data on this scale. So while the GDELT data offers an avenue to answer some existing questions, it also brings with it many potential problems.

Careful Research

So, that all sounds kind of depressing. We have this new, cool dataset that could be tremendously useful, but it also presents many hurdles. What, then, should we as social science researchers do about it? My answer is careful theorizing and thinking about the processes under examination. This might be a “well, duh” moment to those in the social sciences, but I think it is worth saying when there are some heralding “The End of Theory”. This type of large-scale data does not reduce theory and the scientific method to irrelevance. Instead, theory is elevated to a position of higher importance. What states do I want to look at? What type of actions? Well, what does the theory say? As Hilary Mason noted in a tweet:

Data tells you whether to use A or B. Science tells you what A and B should be in the first place.

Put into more social-scientific language, data tells us the relationship between A and B, while science tells us what A and B should be and what type of observations should be used. The data under examination in a given study should be driven by careful consideration of the processes of interest. This idea should not, however, be construed as a rejection of “big data” in the social sciences. I personally believe the exact opposite; give me as many features, measures, and observations as possible and let algorithms sort out what is important. Instead, I think the social sciences, and science in general, is about asking interesting questions of the data that will often require more finesse than taking an “ANALYZE ALL THE DATA” approach. Thus, while datasets like GDELT provide new opportunities, they are not opportunities to relax and let the data do the talking. If anything, big data generating processes will require more work on the part of the researcher than previous data sources.

John Beieler is a Ph.D. student in the Department of Political Science at Pennsylvania State University. Additionally, he is a trainee in the NSF Big Data Social Science IGERT program for 2013-2015. His substantive research focuses on international conflict and instances of political violence such as terrorism and substate violence. He also has interests in big data, machine learning, event forecasting, and social network analysis. He aims to bring these substantive and methodological interests together in order to further research in international relations and enable greater predictive accuracy for events of interest.

This week, the Global Data on Events, Location, and Tone, or GDELT dataset went public. The architect of this project is Kalev Leetaru, a researcher in library and information sciences, and owes much to the work of Phil Schrodt.

The scale of this project is nothing short of groundbreaking. It includes 200 million dyadic events from 1979-2012. Each event profiles target and source actors, including not only states, but also substate actors, the type of event drawn from the Schrodt-specified CAMEO project, and even longitude and latitude of the event for many of the events. The events are drawn from several different news sources, including the AP, AFP, Reuters, and Xinhua and are computer-coded with Schrodt’s TABARI system.

To give you a sense how much more this has improved upon the granularity of what we once had, the last large project of this sort that hadn’t been in the domain of a national security organization is King and Lowe’s 10 million dyadic events dataset. Furthermore, the dataset will be updated daily. And to put a cherry on the top, as Jay Ulfelder pointed out, it was funded by the National Science Foundation.

For my own purposes, I’m planning on using these data to extract protest event counts. Social movement scholars have typically relied on handcoding newspaper archives to count for particular protest events, which is typically time-consuming and also susceptible to selection and description bias (Earl et al. 2004 have a good review of this). This dataset has the potential to take some of the time out of this; the jury is still out on how well it accounts for the biases, though.

For what it’s worth, though, it looks like it does a pretty bang-up job with some of the Egypt data. Here’s a simple plot I did across time for CAMEO codes related to protest with some Egyptian entity as the source actor. Rather low until January 2011, and then staying more steady through out the year, peaking again in November 2011, during the Mohamed Mahmoud clashes.

These data have a lot of potential for political sociology, where computer-coded event data haven’t really made much of an appearance. Considering the granularity of the data, that it accounts for many substate actors, social movement scholars would be remiss not to start digging in.

A few other resources on GDELT:
Leetaru and Schrodt’s 2013 ISA paper
Jay Yonamine‘s (one of Schrodt’s students) paper on predicting levels of violence in Afghanistan

Bad Hessian

Hack the World-System

Category Archives: Text analysis

Scraping Historical Newspaper Archives: The Transformation of Public Lynching Discourse in the US

Computer-Assisted Content Analysis and Sociology: What You Should Know

Converting approximating numerical words to numbers?

Challenges of automated Arabic/Persian transliteration

Has R-help gotten meaner over time? And what does Mancur Olson have to say about it?

RuPaul’s Drag Race Season 5 Finale — Predicting America’s Next Drag Superstar from Twitter

GDELT, Big Data, and Theory

Dealing with GDELT

Careful Research

GDELT and social movements