Copy testing is a specialized field of marketing research, that determines an advertisement's effectiveness based on consumer responses, feedback, and behavior.
In 1982, a consortium of 21 leading advertising agencies — including N. W. Ayer, D’Arcy, Grey, McCann Erickson, Needham Harper & Steers, Ogilvy & Mather, J. Walter Thompson, and Young & Rubicam — released a public document laying out the PACT (Positioning Advertising Copy Testing) Principles that constitute a good copy testing system.
For example, Procter and Gamble reviewed 10 year's worth of split-cable tests (100 total) and found no significant relationship between recall scores and sales (Young, pp. 3–30).
This shift was led, in part, by researcher Horace Schwerin who pointed out, “the obvious truth is that a claim can be well remembered but completely unimportant to the prospective buyer of the product – the solution the marketer offers is addressed to the wrong need” (Honomichl).
Non-verbal measures were developed in response to the belief that much of a commercial's effects – e.g. the emotional impact – may be difficult for respondents to put into words or scale on verbal rating statements.
The most popular of these was the dial-a-meter response which required respondents to turn a meter, in degrees, toward one end of a scale or another to reflect their opinion of what was on screen at that moment.
Rita Kirk and Dan Schill from Southern Methodist University worked with CNN to gauge voters reaction to debates between presidential hopefuls.