1. ROC Curves
Receiver Operating Characteristic (ROC) curves are used to determine the appropriate operating point of a system, the tradeoff between False Accept Rate (FAR) and False Reject Rate (FRR)
The operating point can be set to be
Very Liberal (in authenticating, not politically liberal)
Very Conservative
Somewhere in between
-FAR = False Accept Rate – the rate an imposter is falsely accepted.
-A low FAR is a measure of high security-FRR = False Reject Rate – the rate the correct person is falsely rejected
-A low FRR is a measure of high convenience

2. Supreme Court Analogy Usual Supreme Court Majority Decision
Authenticate on at least five judges accepting.
Introductory notes.

3. Supreme Court Analogy Very Conservative (Unanimous) Decision
Authenticate only if all 9 judges accept.
Positive classification requires strong evidence.

4. Supreme Court Analogy
Conservative – 8, 7, or 6 votes needed for decision
Authenticate on at least 8, 7, or 6 judges accepting.
Introductory notes.

5. Supreme Court Analogy Liberal – 4, 3, or 2 votes needed for decision
Authenticate on at least 4, 3, or 2 judges accepting.
Introductory notes.

6. Supreme Court Analogy Very Liberal. 1, or 0 votes needed for decision
Authenticate if only 1 or perhaps no judge accepts.
Introductory notes.