code for determining {TAIL ~ a second set} of candidates from {HEAD ~ the first set} of candidates who have passed testing procedures; and 
code for determining { TAIL ~ a second set } of candidates from { HEAD ~ the first set } of candidates who have passed testing procedures ; and
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH