Health messages can be generic, targeted to population subsets or tailored for individual recipients. There has been little examination of which populations need tailored interventions or whether tailored and targeted interventions differ in important ways. We used data from a mammography intervention study in two distinct populations to simulate a comparison of individually tailored versus targeted interventions. Tailored intervention content was based on individual recipients' interview responses. Targeted intervention content was based on composite group responses. For more than 60% in each population group, about two-thirds of tailored message content was a good match with content of the targeted intervention generated by composite group responses; roughly one-third of the content was 'not a good' fit for their intervention needs. Tailored interventions for more than 80% of subjects in each population differed in at least some way from those generated for all other population group members. This simulation is a first step in quantifying the contribution of individual tailoring over group targeting. Future research should examine whether a targeted intervention that is mostly a 'good' match results in behavioral outcomes similar to those of individually tailored interventions and whether particular differences in tailored versus targeted interventions yield significantly more favorable intervention outcomes.
