PhD or research is all about finding out new concepts. Thus we provide a deeper in already existing knowledge. PhD in Social Science is very much different from that of pure sciences, yet the goal is the same. As you know for doing research/PhD at the university level, the qualification required is PG degree. Every university has different criteria for selecting candidates.
As you know DSE, JNU, ISI, IEW, IIPA, and IIMs are the prime institutions for teaching, learning and researching in economics, management and public administration.
If you are willing to get into one of these institutions, a Master’s from IGNOU will have the same value as that from any other university. To get selected into these prestigious institutions, you will have to pass through a rigorous selection process of
Entrance
Group discussion
Personal interview
Moreover you will have to provide testimonials from your professors about your academic developments.