Duke-Heidelburg quotient
The Duke-Heidelburg quotient was, in the field of 23rd century psychology, a relative means for determining the potential in one's abilities of possessing extrasensory perception; especially when used in correlation with the esper rating, aperception quotient, and general knowledge quotient.
According to a readout on Dr. Elizabeth Dehner in 2265, she had a Duke-Heidelburg quotient rating of 256. Her ratings were considered "better than average."
Likewise, Gary Mitchell had a Duke-Heidelburg quotient rating of 261. His ratings reached into the next level of "well above average." (TOS: "Where No Man Has Gone Before")

Dehner's Duke-Heidelburg quotient

Mitchell's Duke-Heidelburg quotient
Both names attached to the quotient belong to universities.