a record clustering system provides a computationally inexpensive method of accurately clustering data records containing structured raw data requiring only two passes over the data . each data record contains a sequence of attribute values of corresponding attributes . for each attribute , a characteristic value is calculated by evaluating the attribute values of that attribute across the data records . for each attribute value , a deviation from the corresponding characteristic value is calculated . the attributes of each record are sorted based on the deviations to provide a sequence of attributes used as a key for clustering . a user may select criteria for evaluation of the keys for clustering of the data records . the clustering result is refined by searching of best matching keys in other clusters for the records of the smallest cluster . in this manner , the records contained in the smallest cluster are distributed to other clusters , reducing the total number of clusters .