**Abstract**
The National Library of Medicine (NLM) has discontinued a very helpful feature that enables users to find related citations for a set of citations. PubMed does not have a name for this feature; in this commentary, we propose the label “Similar-to-set.” PubMed has so many useful features, we believe many PubMed users are not aware of Similar-to-set. The importance of this Similar-to-set is that it gives PubMed users an easy search tactic that is an alternative to difficult Boolean searches that require selecting best search terms and combining them with Boolean logic. We encourage users of PubMed who have used this feature and liked it to contact the NLM.
We encourage users who are unfamiliar with this feature to read this commentary and test this feature in Legacy PubMed [https://pmlegacy.ncbi.nlm.nih.gov/] which is available through October, 2020. We provide a short, 47 second demonstration video [http://sumsearch.org/searching/#alternatives]. If you like the Similar-to-set feature, please contact the NLM using the green “feedback” button at the bottom of any page at the new PubMed [https://support.nlm.nih.gov/support/create-case/].
The full text of this proposal at the Open Science Foundation (OSF) is at [https://osf.io/ug7vq/].
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> Addendum (10/07/2020): when we have contacted the NLM, their response is that the many databases indexed on PubMed are no longer on the same platform with PubMed and so the "Find Related Data" feature is no longer possible. Consider including in your suggestion to PubMed that we are only asking for PubMed to find related data that is within itself and so the other databases are not needed.
