A method of improving the speed with which a sample such as a biometric sample can be fuzzily matched against records in a database, comprises extracting characteristics from the sample, and using those extracted characteristics as indexes (70) to address a lookup table (25). Each row within the lookup table points to an individual record occurrence list (28, 30, 32) which contain details of not only the stored records from which the given characteristic can be extracted, but also those records having an extracted characteristic which are within a defined proximity to the said characteristic. Characteristics are extracted from the sample record, and a given stored record is identified as being a possible match with the sample if it appears in a required number of record occurrence lists.