Notwithstanding the need for common classifications, data sources also need to be mutually coherent. Currently-available sources, both from private and public sources, do not yet live up to this requirement. This is a significant concern for policymakers.
There could be various sectors of the economy which may deserve a preferential treatment taking into account their national relevance. It would be in order to lighten the burden of Basel II on these sectors within the  5/7  limitations of national discretion provided the resulting capital requirements reflect the underlying risks in these sectors.