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Are invalid patents still cited?
Author(s) -
Dong HueiRu,
Chen DarZen,
Huang MuHsuan
Publication year - 2019
Publication title -
proceedings of the association for information science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.193
H-Index - 14
ISSN - 2373-9231
DOI - 10.1002/pra2.117
Subject(s) - sample (material) , chemistry , chromatography
Patents contain reference citations. However, unlike journal papers, patents may become invalid if they are not maintained or have expired. This study determines whether invalid patents are still cited. We collected telecommunications patents as a sample to compare the citations of valid and invalid patents. The results indicated that approximately 50% of cited patents were invalid. Furthermore, the citations per patent of invalid patents were fewer than those of valid ones. Nevertheless, the citations per patent of invalid patents were reduced 5.21, and nearly 5% of the patents were cited only after they became invalid.