Anchor: Validity (as used here) refers to whether the data actually represent what you think is being measured.
Entailed: Data is valid if it accurately represents what you believe is being measured.
Contradiction: The data is only valid if you think it is being measured correctly, not if it actually represents what you think is being measured.
Contradiction: If we miss something there's absolutely no chance of being able to catch it at a later time. 
Contradiction: two guys sitting at computers
Contradiction: Hunt and Johnny were not close and had never met. 
Contradiction: He saw the guy who cut the line and confronted him.