8. The method of claim 7 , wherein determining a level of ambiguity comprises: determining the number of unambiguous matches between elements of the first and second schemas; determining the number of ambiguous matches between elements of the first and second schemas; determining the number of impossible matches between elements of the first and second schemas; and calculating the level of ambiguity based on the number of unambiguous matches, the number of ambiguous matches, and the number of impossible matches.
7. A computer-implemented method for identifying matches between disparate schemas, the method comprising: calculating, using a data processing apparatus, a first degree of similarity between elements of a first schema and elements of a second schema using a first matching process, each of the first and second schemas comprising data elements stored in a computer-readable storage medium; calculating, using the data processing apparatus, a second degree of similarity between the elements of the first schema and the elements of a second schema using a second matching process; combining, using the data processing apparatus, the first degree of similarity and the second degree of similarity using a first weighting vector to provide a combined degree of similarity, the first weighting vector comprising a first weighting coefficient corresponding to the first matching process and a second weighting coefficient corresponding to the second matching process; determining, using a data processing apparatus, a level of ambiguity based on the first combined degree of similarity, the level of ambiguity accounting for at least one of a number of unambiguous matches between elements of the first and second schemas, a number of ambiguous matches between elements of the first and second schemas and a number of impossible matches between elements of the first and second schemas; and adjusting, using a data processing apparatus, the first weighting coefficient and the second weighting coefficient based on the level of ambiguity to provide a second weighting vector by receiving user feedback relating to a subset of possible matches between the elements of the first schema and the elements of the second schema, the first coefficient and the second coefficient being adjusted based on the user feedback.