The percentage of cell phone only households in the United States continues to rise and currently hovers just under 32% (Bloomberg and Luke, 2011). With a
continually increasing rate nearly 50% of U.S. mobile phone subscribers use smartphones (Rainie et al., 2012 and Nielsen Wire, 2012). As these smart mobile
devices continue to rise in popularity and functionality, their potential as a survey data collection methodology becomes clearer. This paper presents the preliminary
results of an experiment that randomized online panelist to complete an online survey via computer or iPhone within 8 block groups defined by a combination of age, sex
and education variables. Detailed comparisons for mode effects from two broad outcomes including: randomization/recruitment and survey process/completion are
included in this paper. In short, there were significant differences noted in survey completion times after accounting for block group. No significant differences were
noted for other key mode effects outcomes including open ended items and missing item rates, contrary to what we would have expected.