Behavioral Measurement as Centerpiece.

Hank Pennypacker's interest in behavioral measurement began early in his career and gradually became the centerpiece of his diverse accomplishments. A review of his focus in the 1960s is followed by a brief summary of the evolution of behavioral measurement practices in applied behavior analysis as it emerged from the field's laboratory history. This examination serves as pretext for a discussion of the contributions of (Johnston & Pennypacker, 1980), (Johnston & Pennypacker, 1993a, 2009), and Johnston et al., 2020) to emerging matters of behavioral measurement. That discussion focuses on how issues raised by the challenges of applied research and practice have evolved.