Use this sociology calculation to reproduce a named demographic, inequality, mobility, urban, or survey measure when the population, period, categories, and coding rules are explicit.

First city

Required number. Largest city population.

Second city

Required number. Second city population.

Third city

Required number. Third city population.

Fourth city

Required number. Fourth city population.

The cited overview of Sociology supplies background for the terminology and domain context used by this tool.^[1]

Score urban primacy as the largest city's population over the combined next three cities. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

Four-city primacy

Returned number. Primacy ratio; values near or above one mark a primate city system.

• Definitions, sampling error, missing data, historical context, geographic boundaries, weighting, and classification choices can materially change social indicators and their interpretation.
• First city must be at least 0.
• Second city must be at least 0.
• Third city must be at least 0.
• Fourth city must be at least 0.
• Use finite inputs in the displayed units, preserve source measurements and assumptions, and independently verify consequential decisions.

Report the source population and uncertainty, inspect disaggregated data, and compare multiple accepted indicators rather than treating one summary statistic as a complete social explanation.

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