Instructions for updating strategies used in searching thematic areas of the VHL

In view of the annual update carried through in the MeSH vocabulary which is then incorporated into DeCS, as well as changes in other DeCS categories, the need for the revision and update of the search strategies of the thematic areas of the VHL have become crucial. This revision applies both to the strategies that use descriptors as well as to those using hierarchic codes.

To achieve the update of the strategies, the addresses for the two versions of DeCS are available, where consultations using the alphabetical, hierarchic and kwic (keyword in context) indices can be made:

- version 2007 from which the strategies were based: DeCS 2007 Search

- version 2008 from which the strategies must now be based: DeCS 2008 Search

Besides the information available under "DeCS news", DeCS 2008 edition regarding the changes occurred in 2008, the link under “DeCS previous editions”, for the DeCS 2006 edition, contains more detailed information with respect to the important revision of the Public Health category concluded that year, of the descriptors that were modified and eliminated, as well as information of previous DeCS editions.

In order to update search strategies containing hierarchic codes (or tree numbers) from MeSH categories, see changes taken place between the years 2007 and 2008 in the following tables:

Methodology for updating search strategies

- check if hierarchic codes and/or descriptors of your strategy are still valid in the DeCS 2008 version

- if so, leave them as they are

- if not found, check in version 2007 which descriptor the hierarchic codes belonged to and look for the new descriptors and respective hierarchic codes in version 2008

- see also the ‘DeCS 2008 edition’ link under ‘DeCS news’ in the following page: decs2008i.htm

See below an example of a strategy which was updated:

Before updating:

(ex SP4.405.350.364$ or ex SP8.473.654.412.052.080.115.020.020$ or ex D05.723$ or ex D27.720.723$) or (ti Pesticide$ or ti Plaguicida$ or ti Praguicida$) [Subject descriptor]

Updating that was made:

      SP4.405.350.364

This hierarchic code which in 2004 corresponded to the Pesticides descriptor in SP4 (Environmental Health) was modified. The new 2006 hierarchic code for the descriptor in the SP4 (Environmental Health) category is: SP4.001.022.238.

      Explode, truncation

The "ex" (from explode) that precedes the hierarchic code and the “$" sign (truncation), indicate that the Pesticides descriptor and all its more specific descriptors will be included in the recovery of literature.

      SP8.473.654.412.052.080.115.020.020

This hierarchic code, that continues to exist, also belongs to the Pesticides descriptor since, being DeCS polyhierarchical, a descriptor can be located in more than one of its categories/subcategories. It is not necessary to again include in the strategy this descriptor or the other hierarchic branch where the descriptor is found, because it is already also duly contemplated in SP4.001.022.238.

      Unnecessary truncation

Another detail for the elaboration of the strategies is that when a hierarchic code of a descriptor is used under which there is no other more specific descriptor, it is unnecessary to follow it with the “$” sign

      D05.723

This hierarchic code does no longer appear in version 2004 of DeCS, since the D05 subcategory of MeSH was eliminated in 2004. Its content was transferred to the D27.888 subcategory. In 2005 the D05 subcategory was recreated by MeSH but with other content: Macromolecular Substances.

      Title words

The words of the title continue in the search strategy expression without alterations.

      Pesticides [D27.720.723] and Pesticides [D27.888.723]

These hierarchic branches are almost identical, except for the descriptor Pesticide Residues, present in the D27.888.723 branch and absent in the D27.720.723 branch

One should remember that the same descriptor can be inserted in different hierarchies in the DeCS tree, with variations in the specific descriptors. If it is necessary to consider different specific descriptors, the different hierarchic branches can be included in the strategy

Final recommendation

Thus, contemplating all the existing specific descriptors in the various hierarchic branches where the descriptor Pesticides is inserted, the new search strategy must be as follows:

(ex SP4.001.022.238$ or ex D27.888.723$) [Subject descriptor] or (ti Pesticide$ or ti Plaguicida$ or ti Praguicida$) [Title words]

Annex:

Cited hierarchic branches in the example in the two versions of DeCS:

DeCS 2004:

Pesticides [D27.720.723]

Pesticides [D27.888.723]

Pesticides [SP4.405.350.364]

Pesticides [SP8.473.654.412.052.080.115.020.020]

Pesticides [D27.720.723]

Pesticides [D27.888.723]

Pesticides [SP4.001.022.238]

Pesticides [SP8.473.654.412.052.080.115.020.020]