“If you build it, he will come.”
—VOICE OF RAY LIOTTA AS SHOELESS JOE JACKSON IN Field of Dreams (1989)
As data scientists, we do more than work with existing data. Often we are asked to conduct primary research, design experiments, and conduct surveys, many of them relating to new products. Which is to say that modeling techniques in predictive analytics are often preceded by measurement.
The classic article by Campbell and Fiske (1959) provides a clear definition of reliability and validity: Reliability is the agreement between two efforts to measure the same trait through maximally similar methods. Validity is represented in the agreement between two attempts to measure the same trait through maximally different methods. (83) ...