Die jüngste Studie des Europäischen Instituts für öffentliche Verwaltung (EIPA) „The Institutional Impacts of EU Legislation on Local and Regional Governments, A Case Study of the 199/31/EC Landfill Waste and 2004/18/EC Public Procurement Directives“, beklagt unter anderem den starken Einsatz nicht zwingender Rechtsinstrumente: „using soft law to regulate very important aspects of the Directive is another important shortcoming: it is not possible to foresee the institutional impact of soft law“.
In het meest recente onderzoek van het Europees Instituut voor Bestuurskunde (EIB) – "The Institutional Impacts of EU Legislation on Local and Regional Governments, A Case Study of the 199/31/EC Landfill Waste and 2004/18/EC Public Procurement Directives" – wordt onder meer geklaagd over de grote invloed van dit type recht: "using soft law to regulate very important aspects of the Directive is another important shortcoming: it is not possible to foresee the institutional impact of soft law".