One of the biggest hurdles to qualifying an initiative for the ballot is gathering the required number of signatures. Yet little is known about these signatures' representativeness or demographic origin. Using data from eight recent California initiatives, we study the distribution of signatures across counties. We ten conduct regression analysis to study how characteristics of counties relate to the number of signatures gathered there. Besides the sources of petition signatures, we also study the results of checks performed by county officials on these signatures to determine whether there are sufficient valid signatures (i.e., from registered voters) in order to qualify the petition for the ballot. We then conduct regression analysis of validity rates by county. Our findings indicate that a variety of social and political factors influence both the number and validity rate of signatures across counties, though the results are more consistent for the former. Finally, we demonstrate that signature gathering campaigns have consequences for outcomes by relating the intensity of the signature campaign within a county to ballot roll-off.