"Dissertation Timespans"

Ben Schmidt, March 29, 2015

I wrote a few posts back in 2013 about the changing time spans covered in history dissertations. Some of that data has since played a role in a fairly bitter exchange in the American Historical Review about the relative merits of short-term and long-term history, including a number of forays into other data sets. Anticipating this and wanting a nice collection of texts for teaching, I recently got a big collection of reviews in the American Historical Review (and a literary studies journal, to boot). All participants now seem to agree that the time span of history dissertations has been increasing since around the mid-1970s. Can this data tell us anything more about just why that happened?

Here’s a chart that simply shows, broken up into decades, the raw number of reviews falling into the three major lengths of time covered.

Number of books covering each of three magnitudes of time reviewed in the AHR, 1890-2010, by decade

{
"database": "jstor",
"plotType": "streamgraph",
"method": "return_json",
"search_limits": {
 "journaltitle":["The American Historical Review"],
 "span":{"$gt":0},
},
"aesthetic": {
 "y": "TextCount",
 "fill": "*generalBin",
 "x": "decade"
}
}

(With all of these, you have to click the grey square to reveal the chart itself).

Far and away the most salient point on this chart is: the number of monographs in history reviewed in the AHR exploded in the 1970s. This could, of course, be simply due to a change in the journal itself. But in fact, the same pattern (roughly) holds in the dissertation dataset as well: a massive explosion (about 5 years earlier). (I continue using the AHA set instead of Proquest because it’s public domain. Perhaps Lincoln Mullen or someone can confirm if there are major differences between the two).

Number of Dissertations in the AHA’s dataset.

{
"database": "historydiss",
"plotType": "linechart",
"method": "return_json",
"search_limits": {"year_year":{"$gte":1930}},
"aesthetic": {
 "y": "TextCount",
 "x": "year_year"
}
}

It’s kind of crazy to compare the historical profession from before 1975 to that after. We all still keep some reflexive idea that the field “professionalized” in the late 19th century with the creation of the AHA, the major departments, and the like: but that explosion in book reviews is just one of several things that should remind us that the 1970s were at least as important in turning history from an avocation into an occupation.

So: lets set the focus a little bit more specifically on the period after 1970, and look at the changing periods then.

I’ll make this a little easier by doing it as a line chart. Here the percentage is expressed as a ratio of the total number of dissertations for which I could impute lengths. As of the time of writing, I have not attempted to turn “19th century” in “1800-1899,” because it’s quite a fuzzy proposition. Guldi and Armitage’s work don’t clarify how they accomplished this same feat.

Percentage of dissertations covering different time periods, since 1970

{
	"database": "jstor",
	"plotType": "linechart",
	"method": "return_json",
	"search_limits": {
	"journaltitle":["The American Historical Review"],
	"span":{"$gt":0},
	"publication_year":{"$gte":1970}
},
"aesthetic": {
 "y": "TextPercent",
 "x": "publication_year",
 "color":"*generalBin"
}
}

Percentage of dissertations covering different time periods, since 1970, whose reviews use the word “Europe”

{
"database": "jstor",
"plotType": "linechart",
"method": "return_json",
"search_limits": {
 "word":["europe","european"],
 "journaltitle":["The American Historical Review"],
 "span":{"$gt":0},
 "publication_year":{"$gte":1970},
 "*generalBin":[]
},
"aesthetic": {
 "y": "TextPercent",
 "x": "publication_year",
 "color":"*generalBin"}
}

Percentage of dissertations covering different time periods, since 1970, whose reviews use the word “Asia” or “Asian”

{
"database": "jstor",
"plotType": "linechart",
"method": "return_json",
"search_limits": {
 "word":["asia","asian"],
 "journaltitle":["The American Historical Review"],
 "span":{"$gt":0},
 "publication_year":{"$gte":1970},
 "*generalBin":[]
},
"aesthetic": {
 "y": "TextPercent",
 "x": "publication_year",
 "color":"*generalBin"}
}

Percentage of dissertations covering different time periods, since 1970, whose reviews use the word “America” or “American”

{
"database": "jstor",
"plotType": "linechart",
"method": "return_json",
"search_limits": {
 "word":["america","american"],
 "journaltitle":["The American Historical Review"],
 "span":{"$gt":0},
 "publication_year":{"$gte":1970},
 "*generalBin":[]
},
"aesthetic": {
 "y": "TextPercent",
 "x": "publication_year",
 "color":"*generalBin"}
}