There are different dimensions to support the assessment and benchmarking of the social value of open data initiatives. We propose a methodology that compares and evaluates open data social value according to a spectrum of measures going from intensional completeness to subjective meaning. We first suggest that open data made available online by an organization can be modelled in terms of the corresponding integrated conceptual schema, as a uniform construct. Then, a global schema is created with the integrated schemas, and intensional as well as extensional social value on data can be defined over such conceptual schemas.