1. Query translation
The search portal extends the query with translations of the contained terms and phrases. It then queries the extended version.
erroneous translations impair the quality of the results
2. Content translation
Translation of the relevant parts of the portal's content (metadata and abstracts) into all other languages.
fast search due to lack of on-line translation
four language pairs require twelve translation directions
due to the varying amounts of training material for the different language pairs, the quality of automatic translation could differ greatly
3. English as a pivot language
Online translation of all search queries and offline translation of the database, each into English.
only three translation processes required
translations into English are most likely of highest quality
separate translation of search queries and database can lead to errors in two places
4. Knowledge-based approach
Terms contained in the search query are mapped on-line onto specialist thesauri
can be combined with any of the previous methods
PubPsych datasets use multiple controlled vocabularies, which would require mapping the different terms onto each other