Of the entire database, the number of thesis titles with a colon is 43 percent, but over time that number has increased dramatically. The trend slowly built popularity before leveling out after the 1980s.

There is a large dip between the years 1987 and 1990, but there doesn’t seem to be any obvious reason apparent in the data. There were no major shifts between departments and no dramatic jumps in enrollment. I reached out to Cynthia Addison, a Princeton alumna (and colon-user) who wrote her thesis in 1989. She said that this was the first year when all theses were written via a word processor, not a typewriter. She suggested that maybe colons were harder to find on the keyboards used by students, similar to finding foreign characters on a modern keyboard — difficult, but not impossible.

Note: For clarity, “Romance Languages and Literatures” was combined with “French and Italian”, “East Asian Studies Program” was combined with “East Asian Studies”, and “Global Health and Health Policy Program” was combined with “Woodrow Wilson School”.

Logistical factors aside, there is a wide division between academic departments. STEM fields are considerably less likely to contain colons than the humanities. Mathematics is the lowest at 10.6 percent, and African American Studies is the highest at 92.3 percent.

It should be noted, however, that some degrees have very few theses (African American Studies is a new program and only has 13, and Slavic Languages and Literature has only 61), and are therefore more sensitive to becoming outliers. Since more than 1700 theses are filed under the History department from 2000–2019, we should be more confident that the 86.1 percent of them that use a titular colon characterizes the discipline.

The non-STEM department with the lowest colon use is Music with 42.5 percent. And the STEM department with the highest colon use is Psychology with 64.4 percent.

Some seniors used multiple colons (e.g. “Color: From the Cosmetic to the Atmospheric: Redefining the Role of Color for Contemporary Architecture.”) The record? A 7-colon thesis title in 2003 from the English department “‘The:Miscellaneous:Miscellanies:of:the:20th-century:Avante-garde:Poets.Pages.and.Books”. Examples like these are uncommon, however, and theses with more than one colon make up less than 0.5 percent of the database.

Across all thirty thousand titles that contain a colon, it is most common to find three words before the colon, and six words after the colon.

What can this say about academia as a whole? While this database is limited only to proto-dissertations at one university, it’s not unlikely that these numbers highly correlate with what one might find across academic journals (the analysis is possible, but the datasets are less clean). It’s important to consider that Princeton seniors are effectively trying to play the role of an academic. They are likely to mimic, or even exaggerate, trends in the literature that they read.

A similar analysis was performed in the 1980s across education, psychology, and literary criticism. The author of this study praised the idiom’s prolific use, arguing that its popularity demonstrates “the progressive complexity of the scholarly enterprise.” Almost four decades later, can we still make the same argument?