Controlled, In Control, and Out of Control: The Effects of Different Forms of Vocabulary Control on the Subject Indexing and Subject Tagging Processes

Abstract

Subject indexing, the process of determining what a document is about and then translating that "aboutness" into a representation in an indexing language, is fundamental to library cataloging. Subject indexing has historically relied on controlled vocabularies to standardize language and to optimize information retrieval; however, controlled vocabularies have faced criticism for reinforcing systemic biases, for being slow to adapt, and for not reflecting the language and values of many people, especially those from marginalized and underrepresented groups. The emergence of folksonomies in the Web 2.0 era presented a clear contrast to rigorous vocabulary control and promised a more "democratic'' form of knowledge organization that could reflect natural language, adapt quickly, and potentially avoid problems with systemic bias. Folksonomies and social tagging were criticized, though, for being too "uncontrolled'' and, therefore, less effective as information retrieval indexes. This study updates and enriches this comparison of vocabulary control in subject indexing and tagging by identifying five forms of vocabulary control in use today (minimal control, passive control, post hoc control, flexible control, and rigid control), and studying their effect on the subject indexing and subject tagging processes from the perspective of indexers and taggers. The study used a mixed methods approach—including a survey, a think-aloud protocol that was employed while participants indexed and tagged documents, and a retrospective interview—to better understand participants' actions, thoughts, and reactions during the indexing and tagging process. The study explored how controlled vocabularies made participants feel controlled, in control, or out of control while they indexed and tagged; measured how different forms of vocabulary control affected coextensiveness between aboutness statements and indexing terms; and analyzed how these experiences inform the criticisms of controlled vocabularies, particularly for documents about racial and social justice. The study found that the form of vocabulary control had a significant effect on the subject indexing and subject tagging processes, including an effect on participants' feelings of control during the processes, an effect on how participants transformed concepts during subject representation, and an effect on how participants navigated complex issues related to racial and social justice. These findings should help the designers and editors of knowledge organization systems and controlled vocabularies to better and more equitably serve indexers, taggers, information seekers, and the information being indexed and tagged.