The online databases of the Dialog System retrieve only 26% of documents in
an exhaustively compiled collection on the subject of Bradford's Law of Sc
attering, with some documents being retrieved from many databases. However,
when the Exhaustive Collection is more stringently defined to include only
those documents more about the subject, the retrieval rate of Dialog impro
ves to 61%, while its most productive database, LISA, alone retrieves 37%.
Both of these 'samples' give good estimates of the size-invariant propertie
s of the Exhaustive Collection which are typically studied in Bradford and
Growth Analyses - vindicating this use of online searching. However, withou
t additional information, online searches are of little use in determining
size-related properties of subject literature collections. Whether the anal
ysis reported here - which relies on identical interpretations of a 'subjec
t' - has secure foundations is briefly considered.