Perceived Message Effectiveness Meets the Requirements of a Reliable, Valid, and Efficient Measure of Persuasiveness.

Abstract

In every science, the measurement of core quantities requires valid tools: usually a set of procedures or operations. Measurement procedures may vary considerably for assessing the same core attribute. For example, the attribute of physical distance (or length) can be measured in many ways, including the familiar micrometer, ruler, and tape measure, but also the less familiar infrared Helium–Xenon laser interferometry, X-raying opaque materials, Gunter’s chain for surveying (circa 1620), radio navigation using transponders, and rangefinders (as deployed in World War II), among many other techniques. All these tools measure the distance between two points in space comparing the measured distance to some established standard to obtain length. Some procedures are very precise; some expensive; some cheap and easy; and some are designed for specific applications and are necessarily inappropriate for other applications. All of them need to meet core criteria that we might identify as reliability and validity. Using a ruler to measure very large or very small distances will show the ruler to be imprecise. Using laser-based optical techniques to carry out simple measurements of a person’s height will be very precise, but very expensive and resource intensive. The bottom line is obvious: we need measurement tools (i.e., procedures) that are reliable (consistent), valid (accurate), and efficient (precise enough) for the task at hand. Denying that a ruler is a good measure of distance because it cannot determine the diameter of the nucleus of uranium 238 is silly, because it is very useful in a wide variety of other tasks where its reliability, validity, and low resource consumption are clear. So it is with perceived message effectiveness (PME) and its close cousins, such as perceived argument strength (PAS).