This year the National Library of Medicine (NLM) is transitioning the process of MeSH indexing in PubMed from manual to automated.

MeSH (Medical Subject Headings) are assigned to MEDLINE citations for the purposes of enriching the metadata and increasing discoverability.

Until 2022 MeSH indexing was done by human indexers at the National Library of Medicine. Starting 2022 human indexers will only oversee and troubleshoot MeSH indexing.

One of the major benefits of automating the process of MeSH indexing is almost instant appearance of MeSH in MEDLINE citations in PubMed. With manual indexing this was delayed for a few months on average. Citations awaiting MeSH indexing were called In Process citations which could be found by keyword searches only.

The downside of automated MeSH indexing, at least in the beginning, could be, potentially, increase in indexing errors. The NLM will be engaged in the ongoing improvement of MeSH indexing algorithm.

Read more about the transition.