This paper examines a method that aggregates individuals’ opinions when individuals express their yes-no opinions to each candidate. We examine what we call a proportional method, for which there exists a threshold proportion such that an option is chosen/certificated if and only if the share of those who says yes to the opinion is larger than or equal to the threshold. This method is commonly used when it does not have to choose any candidate (or when a large number of candidate can be certificated). We use consistency axioms for changes in voters and in opinions to characterize a class of proportional methods.