A family of syntactic complexity metrics is defined that generates several metrics commonly occurring in the literature. The paper uses the family to answer some questions about the relationship of these metrics to error-proneness and to each other. Two derived metrics are applied; slope which measures the relative skills of programmers at handling a given level of complexity and r square which is indirectly related to the consistency of performance of the programmer or team. The study suggests that individual differences have a large effect on the significance of results where many individuals are used. When an individual is isolated, better results are obtainable. The metrics can also be used to differentiate between projects on which a methodology was used and those on which it was not.