The Board of Immigration Appeals held that the exception to the controlled substance ground of deportability for a "single offense involving possession for one's own use of thirty grams or less of marijuana" is a factual question that may be decided by an immigration judge if the record of conviction is not conclusive. In other words, it is a "circumstance specific" inquiry. It is not a categorical inquiry, where the only question is whether the legal elements of an offense match a federal definition.