Studies of budgetary outputs in public organizations are dominated by the theory of incrementalism. This perspective suggests that expenditure decisions are based on simple rules of thumb. We evaluate the validity of incrementalism by examining the annual spending decisions of 403 English local authorities over 15 budgetary cycles. Two budgetary norms are tested empirically: protect the real level of service provision, and follow central expenditure guidelines. Each of these norms is translated into two decision rules: marginality, or the size of deviations from the norm, and regularity, which refers to the consistency of such deviations over time. Few of the statistical results support the hypothesis that local expenditure decisions are dominated by general budgetary norms or specific decision rules. Our evidence therefore casts doubt on the validity of incrementalism as a theory of local budgetary outputs, and as an explanation of spending decisions in the public sector as a whole.