Table 2.

Terminology associated with cluster searching

Concept	Description
Cluster searching	A systematic attempt, using a variety of search techniques, to identify papers or other research outputs that relate to a single study. This relation may be direct (i.e. “sibling” papers produced from the same study) or indirect (“kinship” studies that inform theoretical or contextual elements of the study of interest).
Key pearl citation	A key work in a topic area, specifically in this context a report of a research study that acts as a retrieval point for related outputs that may help to explicate theory or to understand context.
Kinship study	A study subsequently identified as being related to an original study of interest. Kinship studies may share a common theoretical origin, links to a common antecedent study or a contemporaneous or spatial context.
Sibling paper	A paper subsequently identified as being an output from the same study as an original paper of interest.
Study cluster	A group of inter-related papers or other research outputs that relate to the same single research study.