Instructions for updating strategies used in searching thematic areas of the VHL
In view of the annual update carried out 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 2011 from which the strategies were based: DeCS 2011 Search
- version 2012 from which the strategies must now be based: DeCS 2012 Search
Besides the information available under "DeCS news" regarding the changes occurred in 2012 (DeCS 2012 edition), 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.
Methodology for updating search strategies
In the DeCS 2012 Search, look for the descriptor in the existing strategy using the "exact descriptor" field, or search the hierarchical code in the existing strategy using the tree index to see if it still exists.
- If it exists, fine;
- If the descriptor is not found, check in the list of changed descriptors and in the list of deleted descriptors on the DeCS 2012 edition news page and update its strategy with the descriptor that replaced (or absorbed) it;
- If the hierarchical code is not found, search for it in the tree index of the DeCS 2011 Search and discover the descriptor to which it belonged; then search for this descriptor using the option "exact term" in the DeCS 2012 Search, to find out if it still exists and, if so, what its valid hierarchical code is.
- Example for a DeCS descriptor: the descriptor Water Quality, until 2011 existent in the SP and VS categories, Public Health and Health Surveillance respectively, was included in three MeSH/DeCS's N category, Health Care. Thus, in 2012, its hierarchical codes are
This update should happen in all strategies where these hierarchical codes are used.
- Example for a MeSH descriptor: With the creation of the descriptor Renewable Energy under Energy-Generating Resources in the N category (Health Care) in 2012, the descriptor Biofuels now has one more hierarchical level, in addition to also belonging to the D category (Chemicals and Drugs) under Complex Mixtures. Understand the changes n its hierarchical structure.
See below an example of a strategy for Pesticides, valid until 2004 and its updated strategy for 2006:
(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$) [Subject descriptor]
Updating that was made:
This hierarchic code which in 2004 corresponded to the Pesticides descriptor in SP4 (Environmental Health) was modified. The new 2006 hierarchic code for the descriptor in the SP4 (Environmental Health) category is: SP4.001.022.238.
The "ex" (from explode) that precedes the hierarchic code and the “$" sign (truncation), indicate that the Pesticides descriptor and all its more specific descriptors will be included in the recovery of literature.
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.
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 “$” sign
This hierarchic code does no longer appear in version 2004 of DeCS, since the D05 subcategory of MeSH was eliminated in 2004. Its content was transferred to the D27.888 subcategory. In 2005 the D05 subcategory was recreated by MeSH but with other content: Macromolecular Substances.
The words of the title continue in the search strategy expression without alterations.
Pesticides [D27.720.723] and Pesticides [D27.888.723]
These hierarchic branches are almost identical, except for the descriptor Pesticide Residues, present in the D27.888.723 branch and absent in the D27.720.723 branch
One should remember that the same descriptor can be inserted in different hierarchies in the DeCS tree, with variations in the specific descriptors. If it is necessary to consider different specific descriptors, the different hierarchic branches can be included in the strategy
Thus, contemplating all the existing specific descriptors in the various hierarchic branches where the descriptor Pesticides is inserted, the new search strategy must be as follows:
(ex SP4.001.022.238$ or ex D27.888.723$) [Subject descriptor] or (ti Pesticide$ or ti Plaguicida$ or ti Praguicida$) [Title words]
Cited hierarchic branches in the example in the two versions of DeCS:
2006: Pesticides [D27.720.723] Pesticides [D27.888.723] Pesticides [SP4.001.022.238] Pesticides [SP8.473.654.412.052.080.115.020.020] Last updated in: 02/2012
Last updated in: 02/2012