The individual authentication instances are evaluated based upon: the degree of {TAIL ~ match} between the user provided by the first user during the authentication and the data provided by the first user during his enrollment; the inherent reliability of the authentication technique being used; the circumstances surrounding {HEAD ~ the generation} of the authentication data by the first user; and the circumstances surrounding the generation of the enrollment data by the first user 
The individual authentication instances are evaluated based upon : the degree of { TAIL ~ match } between the user provided by the first user during the authentication and the data provided by the first user during his enrollment ; the inherent reliability of the authentication technique being used ; the circumstances surrounding { HEAD ~ the generation } of the authentication data by the first user ; and the circumstances surrounding the generation of the enrollment data by the first user
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH