A schema code complexity analysis architecture that computes complexity data for output to a code designer. The complexity data can be in the form of a number and/or complexity level. A schema component is provided for processing schema code, and a metrics component, for outputting a complexity value based on complexity of the schema code. In one implementation, the schema code is based on an XML schema, and the metrics component employs a newly-defined variation of a McCabe cyclomatic complexity metric to determine the complexity value. The decisions employed for computing schema complexity can include choices, occurrence constraints, element references to substitution groups, type references to types that are extended or restricted, a multiplicity of root element declarations, and nillable elements.