Does understanding individuals require idiographic judgement?

Idiographic understanding has been proposed as a response to concern that criteriological diagnosis cannot capture the nature of human individuality. It can seem that understanding individuals requires, instead, a distinct form of 'individualised' judgement and this claim receives endorsement by the inventor of the term 'idiographic', Wilhelm Windelband. I argue, however, that none of the options for specifying a model of individualised judgement, to explain what idiographic judgement might be, will work. I suggest, at the end, that narrative, rather than idiographic, understanding is a more promising response to the limitations of criteriological diagnosis.