A really good paper, 'Measurement Methodologies for Legal Empowerment of the Poor', by Adam Masser published in 2009 giving an overview of the many, many definitions, methodologies and indicators that various organisations use to measure 'Legal Empowerment' and related issues.
From the abstract, which summarizes it better than I can:
This paper draws on existing methodologies and theoretical frameworks and argues that a narrowly defined, subject-centric approach to measurement of legal empowerment is key to the monitoring of progress towards legally empowering the poor. It argues that broad macroeconomic indicators and topdown assessments are fundamentally incapable of examining important aspects.