Comparing social tags with subject headings on annotating books: A study comparing the information science domain in English and Chinese

The literature often views the emergence of social tagging as a potential alternative method to controlled vocabulary for organizing and indexing large-scale information resources. In this paper, we present an in-depth examination of the relationship between social tagging and controlled vocabulary-based indexing and organization in two unique contexts: the information science domain and when comparing data gathered from both English and Chinese sources. Our results show that the information science domain has more overlap between social tags and controlled vocabulary-based subject terms. This is reflected in the higher percentage of overlapping terms between tags and subject terms, as well as in the strong similarity (measured by Jaccard's coefficient) in frequently used keywords among tags and subject terms. However, social tags in the information science domain still possess limitations in terms of uncontrolled terms, where inconsistencies and noisy usages exist. Our results also show that language difference does have an impact on social tagging. The numbers of Chinese tags overall and per book are less than those of English tags. The most frequently used English tags are single-word terms, which are different from multi-word controlled vocabulary terms. In comparison, the character difference between the most frequently used Chinese tags and Chinese subject terms is just one character (3 vs 4). However, English and Chinese users do share many similar behaviours when they tag books in the information science domain. Many of the most frequently used tags are shared between the two languages and the patterns of overlap between topical tags and subject terms are also similar between the two languages. Overall, despite the application limitations for social tagging in cataloguing and indexing, we believe that tagging has the potential to become a complementary resource for expanding and enriching controlled vocabulary systems. With the help of future technology to regulate and promote features related to controlled vocabulary in social tags, a hybrid cataloguing and indexing system that integrates social tags with controlled vocabulary would greatly improve people's organizational and access capabilities within information resources. © The Author(s) 2012