Premise: On the other hand, the shared main entry for watershed has twenty-three words in CED but 93 in Cobuild .  And the word waterless is a main entry in Cobuild , explained in twenty words, whereas in CED it is naught but a so-called  undefined runon 'merely mentioned, but not explained explicitly, as a sub-entry at water .  So CED enters more items than Cobuild , but devotes less space to explaining them.

Hypothesis: CED is a more effective system because it has a broader database of items.
Relation: contradiction