Technical Notes - e1
AVLINE® Update - e2
Gold Standard Search - e3
Gold Standard Search
Thank you to everyone who mailed in search strategies in response to the Gold Standard Search article in the September-October 1997 issue of the Technical Bulletin. This feature offers searchers a chance to match wits with NLM staff on a search strategy formulation using PubMed or Internet Grateful Med (IGM). The Gold Standard search strategies are developed here at NLM. The search request published in the September-October 1997 issue was:
Your user asks for information on "Jewish genetic diseases."
Choosing a File
MEDLINE was the file to search for this subject. PubMed is the recommended search engine for MEDLINE for the following reasons:
Introduction to the Search
This search was deliberately defined to be vague and imprecise. If you had a real patron standing in front of you, the first thing to do would be to clarify what the user really wants. Is the intent to find an overview of the subject or perhaps a specific disease such as: breast cancer, colon cancer, Tay-Sachs disease, to name just a few of the conditions that have been linked to particular gene combinations in Jewish populations. Without more information in the reference interview, it would be hard to know if you were doing a good job for this user. However based on the subject as stated, you would need to search the subject as broadly as it was defined.
Analysis of the Search Strategies
The selection of the appropriate MeSH headings was important and, because of the general way in which the search request was worded, not that easily determined. The one obvious MeSH heading was Jews and every entry included this term. In addition, the winning entry also text word searched on ashkenazi* or sephardi* (the * is the truncation/wildcard symbol in PubMed). These two terms represent geographic subdivisions within the Jewish population.
The more difficult part was selecting the various terms to represent the genetic concepts to be encompassed in this strategy. This varied sharply in the submitted searches. One person searched only on Hereditary Diseases [mh]; the winning strategy used many more MeSH headings. The key factor here is the determination of the user's needs and making sure the strategy includes all the search terms necessary to retrieve the citations the user would find relevant.
Search Strategy Suggestions
Using Boolean Search Features
jews OR jewish OR ashkenazi* OR sephardi*
and then click on the Search button you will see a retrieval of over 9,500 as of mid-March. Now, click on the Details button and you will see a screen that will allow you to add more terms to your query or change the terms in your query. See Figure 5A.
Enter Your Subject Terms Without Qualifying Them
If you type in hereditary diseases without any qualification and then click on Search and then click on Details you will see the following display:
("Hereditary Diseases"[MeSH Terms] OR hereditary diseases[Text Word])
The Details button allows you to see the search formulation used with your terms. Searching without restricting to MeSH headings means that PubMed will automatically search your term as a MeSH heading and as a Text Word allowing you to retrieve those records still in process, along with the citations already indexed. In addition, all explodable MeSH headings will automatically be exploded for you. In PubMed it is easier than ever before to search the PREMEDLINE and MEDLINE files simultaneously. Just allow the PubMed search engine to look for your term as a Text Word also by not qualifying with MH or not selecting MeSH Terms in the Advanced Search field menu (use the default All Fields for subject searching).
When to Qualify Your Subject Terms
Using The MeSH Browser
All the underlined terms link to a screen displaying more information about the heading. All the MeSH headings with plus signs are explodable and may be clicked on to display the terms underneath them. For instance, you might decide that Neonatal Diseases and Abnormalities should be included in your search terms and if you click on that term you will see the display for that tree. If you click on [Add to Query], the term next to it will be added to your search in the Advanced screen mode. If you wish to stay in the Basic search mode, highlight the term and then copy it and paste it into the Basic search screen. If you click on the [Detailed Display] link next to Hereditary Diseases you will see the screen shown in Figure 2.
The subheadings shown in Figure 2, are those subheadings that have actually been used with the MeSH heading in the MEDLINE data, as compared to the listing in the online ELHILL MeSH database which shows all the allowable qualifiers (subheadings) for a MeSH heading, whether or not they have been used.
Use the Details Button to Edit your Search
For example, in the first search box for the Gold Standard search, the following terms were typed in:
jews OR jewish OR ashkenazi* OR sephardi*
The Details box displayed the following:
You can edit this search statement right in the Details box. To change the field designation from MeSH term to Majr (this is the equivalent of starring (*) a term in ELHILL), with your mouse highlight the contents of the tag [MeSH Terms], type in majr and then click on the Search button at the bottom of the Details Box to rerun your strategy as reformulated. Click on Details again to view the new strategy and to allow yourself to make further modifications.
You can also use the Details box to add Boolean search statements to your search. For example you could modify the search above to restrict retrieval to English language and review articles by adding the last two AND statements shown below:
*Very Important Hint*
PubMed Displays the Citations
After you click on Search in the Basic search screen or in the Details box, you are brought to a screen displaying the citations in brief format, called the Document Summary page. A few citations in brief format are shown below:
Clicking on Abstract report will allow you to change the format display to citation report or MEDLINE report if you so choose. You may select citations by clicking on the box to the left of the citations and then clicking on Display. You may display all the citations on the page by clicking on the Display button without making any selections. You may display a single citation by clicking on the underlined author link. After you display a citation, any available links from that citation to other sites become visible.
PubMed Links To Other Databases and to Full Text
Two citations are shown below. The first is displayed in Citation format and the second citation is displayed in Abstract format. Both citations show the link buttons. The citation format shows the MeSH headings in a non-tagged display. Note that the MEDLINE display format is available to you by clicking on the button saying MEDLINE. Clicking on the OMIM button from the citation shown in Figure 3 below takes you to the Online Mendelian Inheritance In Man database where you will be able to link to the following two records:
#123400 CREUTZFELDT-JAKOB DISEASE; CJD
The Next Gold Standard Search
The search request is:
Customer satisfaction with health maintenance organizations.
Results will be published in the May-June 1998 Technical Bulletin. Entries must be received by April 30, 1998 to be considered.
Choose either PubMed or Internet Grateful Med. If you choose PubMed indicate which search screen you used (Basic, Advanced, or Boolean) and if you used any features such as the MeSH browser, See Related Button, or links to other sources. If you choose IGM, please indicate which database(s) you searched. Limit your retrieval to English language citations.
There are no exact answers or absolutely correct strategies, only best approximations, just like real life. Good luck!
If your strategy is selected for publication you could win an NLM T-shirt or mug. In cases of multiple submissions of identical winning strategies, the prize winner will be either the person who is a first time winner or the first winning strategy received.
Mail us a copy of your search strategy and include a printout of citations. Please note that in the interest of saving time and postage we are no longer asking for abstracts.
With PubMed or IGM as your search engine, if you are unable to print the Details box or the screen displaying your search strategy (try Control P (PC) or Command P (Macintosh), please type your strategy on paper for submission and mail it to:
The Gold Standard search shows the Details boxes for each formulation of the search with the retrieval (at the time this was written) and a statement of how it was edited from the previous display.
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