  This article reviews how empirical research of exploratory search is
conducted. We investigated aspects of interdisciplinarity, study settings and
evaluation methodologies from a systematically selected sample of 231
publications from 2010-2021, including a total of 172 articles with empirical
studies. Our results show that exploratory search is highly interdisciplinary,
with the most frequently occurring publication venues including high impact
venues in information science, information systems and human-computer
interaction. However, taken in aggregate, the breadth of study settings
investigated was limited. We found that a majority of studies (77%) focused on
evaluating novel retrieval systems as opposed to investigating users' search
processes. Furthermore, a disproportionate number of studies were based on
scientific literature search (20.7%), a majority of which only considered
searching for Computer Science articles. Study participants were generally from
convenience samples, with 75% of studies composed exclusively of students and
other academics. The methodologies used for evaluation were mostly
quantitative, but lacked consistency between studies and validated
questionnaires were rarely used. In discussion, we offer a critical analysis of
our findings and suggest potential improvements for future exploratory search
studies.
