According to Dahl (1971) there are two dimensions for classifying political regimes: contestation and inclusiveness. This substantive view of democracy classifies the regimes by the means of the outcomes that they produces and not just the institutions they contain. Higher the contestation and inclusiveness scores are, more democratic the regime is.
In this conceptualization, contestation is the extent to which citizens are free to compete for pressing desired policies and outcomes by organising themselves into blocs.
On the other hand, inclusion is determined by the diversity of the people participating in the political processes.
Dahl, Robert A. (1971). Polyarchy; participation and opposition,. New Haven : Yale University Press