Inoculation theory in a direct mail fund raising campaign : controlled field experiment

The purpose of this study was to test empirically the effects of inoculation and forewarning on three separate populations in a direct mail fundraising campaign. Hypotheses were generated from questions arising from demographic data available on the populations as well as on prior research in inoculation theory.

Major findings were that, first, prior exposure to a persuasive communication one week before a direct mail campaign had a significant positive effect on the decision to donate. Secondly, inoculation, forewarning, and no prior message were equally effective in soliciting gifts from previous donors. Third, inoculation and forewarning produced equally significant increases in the rate of giving among previous non-donors. Fourth, inoculation significantly increased the size of gifts by previous donors. Fifth, female subjects gave at statistically equivalent percentages despite the particular treatment received. And, sixth, males responded at a significantly higher percentage to both inoculation and forewarning than to no advance communication.

Implications for future research include the empirical investigation of the same variables over larger populations, an exploration of the effect of time variables, and the application of similar research to other modes of fundraising.