Missing links: Timing characteristics and their implications for capturing contemporaneous technological developments

Abstract

Abstract A missing link in this study refers to a pair of patents whose relatedness is not manifested by one citing the other but implied by their strong bibliographic coupling. By analyzing empirical data, this study discovers that the occurrence of missing links is not coincidental but arises systematically; patent pairs with missing links usually have highly overlapped application processes, whereas those with direct citations more frequently have successive or less overlapped application processes. The missing links thus may capture relatedness between patents that direct citations fail to detect. By applying main path analysis to a network containing 34,083 patents, 155,076 citations, and 9,213 missing links designed to simulate direct citations, this study further finds that the missing links—accounting for only approximately 5% of all connections—identify patents embodying contemporaneous technological developments, which may evade detection if only direct citations are considered.