Conventional electronic information retrieval systems using specialist databases assume that the database being searched is appropriate to the search being conducted.The invention solves the problem that the above assumption may be incorrect. It does this by providing mechanisms (4, 4A and 4B) for identifying concepts respectively in: the search input question, a specialist database and a non-specialist database.A comparator 8 and associated mechanisms are able to analyze how the specialist database differs from the non-specialist database and to use this information to derive an indication of the ability of the specialist database to answer the input question. This indication can be fed to the user via interface 1 or in an alternative arrangement could be used to block inappropriate information.