Monday, April 18, 2011

The 1940 election

A couple weeks ago, I wrote about how structured census data for genealogy, not history, and how that limits what historians can do with it. Last week, I got an interesting e-mail from IPUMS, at the Minnesota population center on just that topic:

We have an extraordinary opportunity to partner with a leading genealogical firm to produce a microdata collection that will encompass the entire 1940 census of population of over 130 million cases. It is not feasible to digitize every variable that was collected in the 1940 census. We are therefore seeking your help to prioritize variables for inclusion in the 1940 census database.

Wednesday, April 13, 2011

In search of the great white whale

All the cool kids are talking about shortcomings in digitized text databases. I don't have anything so detailed to say as what Goose Commerce or Shane Landrum have gone into, but I do have one fun fact. Those guys describe ways that projects miss things we might think are important but that lie just outside the most mainstream interests—the neglected Early Republic in newspapers, letters to the editor in journals, etc. They raise the important point that digital resources are nowhere near as comprehensive as we sometimes think, which is a big caveat we all need to keep in mind. I want to point out that it's not just at the margins we're missing texts: omissions are also, maybe surprisingly, lurking right at the heart of the canon. Here's an example.

Monday, April 11, 2011

Age cohort and Vocabulary use

Let's start with two self-evident facts about how print culture changes over time:
  1. The words that writers use change. Some words flare into usage and then back out; others steadily grow in popularity; others slowly fade out of the language.
  2. The writers using words change. Some writers retire or die, some hit mid-career spurts of productivity, and every year hundreds of new writers burst onto the scene. In the 19th-century US, median author age stays within a few years of 49: that constancy, year after year, means the supply of writers is constantly being replenished from the next generation.
How do (1) and (2) relate to each other? To what extent do the shifting group of authors create the changes in language, and how much do changes happen in a culture that authors all draw from?

This might be a historical question, but it also might be a linguistics/sociology/culturomics one. Say there are two different models of language use: type A and type B.
  • Type A means a speaker drifts on the cultural winds: the language shifts and everyone changes their vocabulary every year.
  • Type B, on the other hand, assumes that vocabulary is largely fixed at a certain age: a speaker will be largely consistent in her word choice from age 30 to 70, say, and new terms will not impinge on her vocabulary.
 Both of these models are extremes, and we can assume that hardly any words are pure A or pure B. To firm this up, let me concretize this with two nicely alphabetical examples of fictional characters to warm up the subject for all you humanists out there:
  • Type A: John Updike's Rabbit Angstrom. Rabbit doesn't know what he wants to say. Every decade, his vocabulary changes; he talks like a ennui-ed salaryman in the 50s, flirts with hippiedom and Nixonian silent-majorityism in the 60s, spends the late 70s hoarding gold and muttering about Consumer Reports and the Japanese. For Updike, part of Rabbit being an everyman is the shifts he undergoes from book to book: there's a sort of implicit type-A model underlying his transformations. He's a different person at every age because America is different in every year.
  • Type B: Richard Ford's Frank Bascombe. Frank Bascombe, on the other hand, has his own voice. It shifts from decade to decade, to be sure, but 80s Bascombe sounds more like 2000s Bascombe than he sounds like 80s Angstrom. What does change is internal to his own life: he's in the Existence period in the 90s and worries about careers, and the 00s he's in the Permanent Period and worried about death. Bascombe is a dreamy outsider everywhere he goes: the Mississippian who went to Ann Arbor, always perplexed by the present.*
Anyhow: I don't have good enough author metadata right now to check this on authors (which would be really interesting), but I can do it a bit on words. An Angstrom word would be one that pops up across all age cohorts in society simultaneously; a Bascombe word is one that creeps in more with each succeeding generation, but that doesn't change much over time within an age cohort.

This is getting into some pretty multi-dimensional data, so we need something a little more complicated than line graphs. The solution I like right now is heat maps.

An example: I know that "outside" is a word that shows a steady, upward trend from 1830 to 1922; in fact, I found that it was so steady that it was among the best words at helping to date books based on their vocabulary usage. So how did "outside" become more popular? Was it the Angstrom model, where everyone just started using it more? Or was it the Bascombe model, where each succeeding generation used it more and more? To answer that, we need to combine author birth year with year of publication:

Sunday, April 3, 2011

Stopwords to the wise

Shane Landrum (@cliotropic) says my claim that historians have different digital infrastructural needs than other fields might be provocative. I don't mean this as exceptionalism for historians, particularly not compared to other humanities fields. I do think historians are somewhat exceptional in the volume of texts they want to process—at Princeton, they often gloat about being the heaviest users of the library. I do think this volume is one important reason English has a more advanced field of digital humanities than history does. But the needs are independent of the volume, and every academic field has distinct needs. Data, though, is often structured for either one set of users, or for a mushy middle.

A particularly clear connection is from database structures to "categories of analysis" in our methodology. Since humanists share methods in a lot of ways, digital resources designed for one humanities discipline will carry well for others. But it's quite possible to design a resource that makes extensive use of certain categories of analysis nearly impossible.

One clear-cut example: The bulk of interest in digitized census records lies in two groups: historians and genealogists. That web site is clearly built for the latter: it has lots of genealogy-specific features built into the database for matching sound-alike names and misspellings, for example, but almost nothing for social history. (I'm pretty sure you can't use it to find German cabinet-makers in Camden in 1850, for example.) views names (last names in particular) as the most important field and structures everything else around serving those up. Lots of historians are more interested in the place or the profession or the ancestry fields in the census: what we take as a unit of analysis affects what we want to see database indexes and search terms built around. (And that's not even getting into the question of aggregating the records into statistics.)

Friday, April 1, 2011

Generations vs. contexts

When I first thought about using digital texts to track shifts in language usage over time, the largest reliable repository of e-texts was Project Gutenberg. I quickly found out, though, that they didn't have works for years, somewhat to my surprise. (It's remarkable how much metadata holds this sort of work back, rather than data itself). They did, though, have one kind of year information: author birth dates. You can use those to create same type of charts of word use over time that people like me, the Victorian Books project, or the Culturomists have been doing, but in a different dimension: we can see how all the authors born in a year use language rather than looking at how books published in a year use language.

I've been using 'evolution' as my test phrase for a while now: but as you'll see, it turns out to be a really interesting word for this kind of analysis. Maybe that's just chance, but I think it might be a sort of indicative test case--generational shifts are particularly important for live intellectual issues, perhaps, compared to overall linguistic drift.

To start off, here's a chart of the usage of the word "evolution" by share of words per year. There's nothing new here yet, so this is merely a reminder:

Here's what's new: we can also plot by year of author birth, which shows some interesting (if small) differences: