Because PubMed and Embase use different controlled vocabularies (MeSH and Emtree, respectively), it's important to take a final look at your PubMed and Embase searches to ensure that their terms match.
In some cases, your Embase search may point you to a MeSH term that you had missed when building your initial PubMed search. Likewise, your Embase search will almost always initially have more keywords than your PubMed search.
It's important to address these differences in terms by harmonizing your PubMed and Embase searches. This helps ensure that the most comprehensive search is run in both databases.
There may be cases when there are imbalances in the number of controlled vocabulary terms between PubMed and Embase searches. This happens when a concept is captured by different numbers of terms in MeSH and Emtree.
For example, the concept "watchful waiting" is captured in MeSH by "Watchful Waiting"[Mesh] and in Emtree by 'watchful waiting'/exp OR 'active surveillance'/exp OR 'expectant management'/exp. Despite the fact that there is one MeSH term and three Emtree terms is these searches, the search elements are harmonized because they properly express the relevant controlled vocabulary terms.
Keywords may not always contribute to results in both PubMed and Embase. PubMed will alert you if no results are found by a keyword. If you receive such an alert you can safely remove the keyword, even if that keyword is represented in your Embase search.
Below are examples of how to perform harmonization for controlled vocabulary and keywords.
In this example, the Emtree keyword "hand hygiene" leads to the discovery of a broader MeSH term, whose child term, "Hand Disinfection"[Mesh], was in your initial PubMed search. This broader MeSH term, "Hand Hygiene"[Mesh], will find its child terms. So, "Hand Hygiene"[Mesh] replaces "Hand Disinfection"[Mesh].
See the cross-out and highlight below.
'hand washing'/exp OR ('hand cleansing' OR 'hand drying' OR 'hand hygiene' OR 'hand sanitation' OR 'hand sanitization' OR 'hand scrubbing' OR 'handscrubbing' OR 'handwashing' OR 'surgical scrubbing' OR 'hand washing'):ti,ab,kw
"Hand Disinfection"[Mesh] "Hand Hygiene"[Mesh] OR "handwashing"[tw] OR "hand washing"[tw] OR "hand sanitization"[tw] OR "hand disinfection"[tw]
In this example, the synonym list from the Emtree record for 'neonatal intensive care unit'/exp includes many keywords that are not included in your initial PubMed search. So, these keywords are added to your PubMed search.
See the highlights below.
'neonatal intensive care unit'/exp OR ('neo-natal intensive care unit*' OR 'neonatal ICU' OR neonatal ICUs OR 'neonatal intensive care department*' OR 'newborn ICU' OR 'newborn ICUs' OR 'newborn intensive care department*' OR 'newborn intensive care unit*' OR 'NICU' OR 'NICUs' OR 'neonatal intensive care unit*'):ti,ab,kw
"Intensive Care Units, Neonatal"[Mesh] OR NICU[tw] OR "neonatal intensive care unit*"[tw] OR "neonatal ICU"[tw] OR "newborn ICU"[tw] OR "neo-natal intensive care unit*"[tw] OR "neonatal ICUs"[tw] OR "neonatal intensive care department*"[tw] OR "newborn ICUs"[tw] OR "newborn intensive care department*"[tw] OR "newborn intensive care unit*"[tw] OR "NICUs"[tw]
Note: Since "newborn intensive care department*"[tw] finds no results in PubMed, it could be excluded from the PubMed search.