The world relies on analyses by the United Nations-facilitated Integrated Food Security Phase Classification (IPC) to identify where populations are food insecure and to quantify the severity of these crises. IPC sub-national analyses are designed to be comparable over space and time in the more than 30 countries in which the IPC operates. Humanitarian agencies appear to regard these findings as authoritative and comparable, and as of 2024, used IPC analyses to guide more than six billion dollars of annual aid allocations. We study the consistency and comparability of IPC food insecurity analyses across time and space. Drawing on 1,849 IPC subnational analyses covering 742 million people from fifteen countries between 2019 and 2023, we show that IPC analyses face significant challenges related to data availability and food security measurement, resulting from underlying food security indicators that are often discordant. We find that the vast majority of IPC subnational analyses are consistent with IPC technical guidance, but that this guidance permits a wide range of classifications for a given set of food security indicators. We also find evidence that IPC subnational analyses vary in the way they use food security data, often weighing food security indicators differently across locations. While variation in how analyses use food security indicators can plausibly reflect varying contextual factors across countries, we find evidence that analyses weight indicators differently across time for the same location. Finally, we show that analyses do not treat closely correlated food security indicators as substitutes, suggesting inconsistency in the treatment of food security indicators across analyses. We discuss implications of these findings for policy and for the interpretation and use of IPC analyses by researchers and policymakers.