Search OVID EMBASE and Get MEDLINE for Free…. without knowing it

19 10 2010

I have the impression that OVIDSP listens more to librarians than the NLM, who considers the end users of databases like PubMed more important, mainly because there are more of them. On the other hand NLM communicates PubMed’s changes better (NLM Technical Bulletin) and has easier to find tutorials & FAQs, namely at the PubMed homepage.

I gather that the new changes to the OVIDSP interface are the reason why two older OVID posts are the recent number 2 and 3 hits on my blog. My guess is that people are looking for some specific information on OVID’s interface changes that they can’t easily access otherwise.

But this post won’t address the technical changes. I will write about this later.

I just want to mention a few changes to the OVIDSP databases MEDLINE and EMBASE, some of them temporary, that could have been easily missed.

[1] First, somewhere in August, OVID MEDLINE contained only indexed PubMed articles. I know that OVID MEDLINE misses some papers PubMed already has -namely the “as supplied by publisher” subset-, but this time the difference was dramatic: “in data review” and “in process” papers weren’t found as well. I almost panicked, because if I missed that much in OVID MEDLINE, I would have to search PubMed as well, and adapt the search strategy…. and, since I already lost hours because of OVID’s extreme slowness at that time, I wasn’t looking forward to this.

According to an OVID-representative this change was not new, but was already there since (many) months. Had I been blind? I checked the printed search results of a search I performed in June. It was clear that the newer update found less records, meaning that some records were missed in the current (August) update. Furthermore the old Reference Manager database contained non-indexed records. So no problems then.

But to make a long story short. Don’t worry: this change disappeared as quickly as it came.
I would have doubted my own eyes, if my colleague hadn’t seen it too.

If you have done a MEDLINE OVID search in the second half of August you might like to check the results.

[2] Simultaneously there was another change. A change that is still there.

Did you know that OVID EMBASE contains MEDLINE records as well? I knew that you could search EMBASE.com for MEDLINE and EMBASE records using the “highly praised EMTREE“, but not that OVID EMBASE recently added these records too.

They are automatic found by the text-word searches and by the EMTREE already includes all of MeSH.

Should I be happy that I get these records for free?

No, I am not.

I always start with a MEDLINE search, which is optimized for MEDLINE (with regard to the MeSH).

Since indexing by  EMTREE is deep, I usually have (much) more noise (irrelevant hits) in EMBASE.

I do not want to have an extra number of MEDLINE-records in an uncontrolled way.

I can imagine though, that it would be worthwhile in case of a quick search in EMBASE alone: that could save time.
In my case, doing extensive searches for systematic reviews I want to be in control. I also want to show the number of articles from MEDLINE and the number of extra hits from EMBASE.

(Later I realized that a figure shown by the OVID representative wasn’t fair: they showed the hits obtained when searching EMBASE, MEDLINE and other databases in Venn diagrams: MEDLINE offered little extra beyond EMBASE, which is self-evident, considering that EMBASE includes almost all MEDLINE records.- But I only learned this later.)

It is no problem if you want to include these MEDLINE records, but it is easy to exclude them.

You can limit for MEDLINE or EMBASE records.

Suppose your last search set is 26.

Click Limits > Additional Limits > EMBASE (or MEDLINE)

Alternatively type: limit 26 to embase (resp limit 26 to medline) Added together they make 100%

If only they would have told us….


3. EMBASE OVID now also adds conference abstracts.

A good thing if you do an exhaustive search and want to include unpublished material as well (50% of the conference abstracts don’t get published).

You can still exclude them if you like  (see publication types to the right)

Here is what is written at EMBASE.com

Embase now contains almost 800 conferences and more than 260,000 conference abstracts, primarily from journals and journal supplements published in 2009 and 2010. Currently, conference abstracts are being added to Embase at the rate of 1,000 records per working day, each indexed with Emtree.
Conference information is not available from PubMed, and is significantly greater than BIOSIS conference coverage. (…)

4. And did you know that OVID has eliminated StopWords from MEDLINE and EMBASE? Since  a few years you can now search for words or phrases like is there hope.tw. Which is a very good thing, because it broadens the possibility to search for certain word strings. However, it isn’t generally known.

OVID changed it after complaints by many, including me and a few Cochrane colleagues. I thought I had written a post on it before, but I apparently I haven’t ;).

Credits

Thanks to Joost Daams who always has the latest news on OVID.

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21 08 2011
PubMed’s Higher Sensitivity than OVID MEDLINE… & other Published Clichés. « Laika's MedLibLog

[...] important aspect to keep in mind when searching OVID/MEDLINE ( I have earlier discussed here and here). But worth a [...]

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