Search Platforms of CAS: SciFinder vs STN

[tweetmeme source=”Intellogist” only_single=false] A popular topic on the CHIMF-L listserv during the past week has been  SciFinder and CAS databases.  Chemical Abstracts Service (CAS) is a division of the American Chemical Society, and the organization produces a variety of chemistry-themed databases, including CAplus, CAS REGISTRY, and MARPAT.  SciFinder is one platform through which to access the CAS databases, but STN (operated jointly by CAS and FIZ-Karlsruhe) offers an alternative platform for CAS database searching.

So which platform offers a higher quality search experience?  Continue reading as I  compare the platforms in three areas: database coverage, ease of use, and Markush searches.

Database Coverage

This comparison reveals a stark contrast: a list of STN Database Summary Sheets shows over 160 databases available through the STN platform, while this chart of databases on SciFinder lists six available databases (a seventh database, MARPAT, is searched during the Markush searches on SciFinder, but results are automatically transferred over to CAplus records).  SciFinder seems to focus solely on searching CAS-produced databases, with the one exception being MEDLINE, a database of biomedical literature produced by the National Library of of Medicine (NLM).  STN, meanwhile, provides access to all CAS databases and a wide variety of non-CAS databases, including well-known patent databases like INPADOCDB and Derwent World Patents Index (WPIDS/WPINDEX/WPIX).  Even the STN Easy interface, which only provides access to a subset of STN databases, still lists over 80 databases searchable through STN Easy.  SciFinder is an excellent resource for a chemistry-focused search, but STN offers a much broader range of databases that can search for patent and non-patent prior art in a wide variety of scientific fields.

Ease of Use

STN has three available interfaces:

  • STN Express: This downloadable software operates on the user’s desktop and uses a combination of command line interface and “Discover! Wizards” programs to search within single databases or database clusters.  All available STN databases are available through this interface.
  • STN on the Web: This command line interface is accessible through a web browser, has “Assistants” to help users conduct searches, and has access to all available STN databases.
  • STN Easy: Users can search a subset of STN databases through this form-based interface accessible through a web browser.

STN users can search through the difficult command line interface of STN Express and STN on the Web, which both provide full coverage of all STN databases (and fully functional structure searching).  Users can also choose the simpler search form interface available on STN Easy, which only can access about half of the STN databases.

STN is accessible through three different interfaces.

Now that SciFinder Scholar is no longer available, all users access  SciFinder through a single web-based log-on.  Users can choose to search for References, Substances, or Reactions,  and each section provides the user with a variety of sleek search forms with an integrated structure drawing tool (for chemical, Markush, or reaction structure searches).  The search forms even provide example search terms to demonstrate how to correctly format a query for a given search field.  Users do not need to learn any complicated command languages to access the full functionality and coverage of SciFinder.

SciFinder has a user-friendly interface with the chemical drawing tool integrated into the search forms.

While professional searchers who are experts in using command line interfaces will appreciate the broad database coverage and flexible functionality of STN Express and STN on the Web, casual or beginner searchers will probably prefer the single user-friendly interface offered by SciFinder.

Markush Searches

Let’s look at a single type of search that can be performed in both STN and SciFinder: a search for generic chemical structures defined in patent claims, called Markush searching.  Markush searches in both STN and SciFinder are conducted in the MARPAT database, but the results in SciFinder are automatically crossed over to to CAplus records.

According to CAS training material for SciFinder:

Markush searches [in SciFinder] are run against the MARPAT database with a predefined set of search parameters that differ in some cases from SciFinder defaults (for example, rings are isolated in Markush searches). Searches are intended to provide focused answers that can be helpful in a preliminary assessment of the patent landscape.

STN is a more powerful platform for searching MARPAT than SciFinder, especially for professional patent searchers, since SciFinder automatically sets certain unchangeable parameters in its Markush search that are customizable through an STN search of MARPAT.  As the training material says, SciFinder can be used for a Markush search to determine a “preliminary assessment of the patent landscape,” but STN will provide a more thorough search for MARPAT records.


STN and SciFinder seem to be platforms geared towards two different user groups.  A professional searcher, like a patent searcher conducting an in-depth search for Markush structures, will choose the more flexible search options and broader coverage provided by STN, while an undergraduate chemistry student will want to conduct their searches on the user-friendly interface of SciFinder.  STN Easy provides an intermediate option for searchers who don’t want to bother with the command language of STN Express or Web but prefer broader database coverage than what is available on SciFinder (although STN Easy doesn’t provide any structure-drawing tools for chemical structure searches).   The bottom line is to choose your CAS search platform based on search skill level and user needs.

Have you used STN or SciFinder?  Which platform do you prefer, based on your profession?  Let us know in the comments!

Patent Analysis from Landon IP

This post was contributed by Joelle Mornini. The Intellogist blog is provided for free by Intellogist’s parent company Landon IP, a major provider of patent searches, trademark searches, technical translations, and information retrieval services.

2 Responses

  1. As a professional searcher, I prefer STN but do not like the associated costs. Under the contract I am on, STN charges for each search and each record viewed. Chemical structure searches can get quite expensive. I frequently review initial search results in PubChem prior to conducting a detailed search on STN.

    • Thanks for the feedback, Mike! I think that’s always been the struggle of the pay-per-search/view model–it’s at odds with our desire to be as expansive and complete as we would like.

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