| Confidence Factor | Description | Characteristics |
| 1 | Nearly Certain | The plate is with the boat. Corroborating evidence exists and/or there is no reason to believe the plate is not original to the boat.
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| 2 | Highly Probable | The plate is with the boat. Corroborating evidence does not exist, leaving the possibility that the plate is not original to the boat, and/or there is a question as to whether the plate is original to the boat.
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| 3 | Probable | The plate is not with the boat, but corroborating, concrete documentary evidence exists.
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| 4 | Possible, with questions | The plate is not with the boat. Corrobrating evidence exists, but it is circumstantial and questions may exist.
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| 5 | Possible, but unlikely | The plate is not with the boat. Corrobrating evidence does not exist.
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