Other than interviews, you can use coding of organizational documents (popular for Advocacy Coalition studies) and more quantitative analysis using either survey data or, if you have access to it and ethics approval, some other form of communication data (eg. email or social media).

That said, your method seems fine. I know that snowball method is also popular for sampling. Of course all of this depends on your research question.

Yes, of course!  Affiliation studies! There are some very good libraries and models for visualizing affiliation networks if you wish to triangulate with quantitative analysis.  One of my favs is Faust, K. (2005). Using correspondence analysis for joint displays of affiliation networks. Models and methods in social network analysis, 7, 117-147.

My doctoral studies focused on the processes of institutional change in Brazilian environmental policy during twenty years (1992-2012), using the Advocacy Coalition Framework (ACF). It applies the ACF in an innovative approach, comparing the subsystems of the green and brown agendas. The green agenda includes issues related to biodiversity and forests, while the brown agenda deals to those relating to pollution control, sanitation and urban environmental management. It studies the decision-making processes of the main national laws on these themes and their results. The database was made by public hearings and other documents produced within the legislative procedures. A coding process of these documents has been conducted, in order to organize information about the actors that were involved in each process, their belief systems and resources, and their influence on the approved laws. The result of qualitative analysis achieved through this coding effort has been controlled with the help of questionnaires filled by experts who participated in the decision-making processes.

I will add to the information that the other colleagues told that depending what is the purpose of your study you have to choose the methodology.

If you want to show the results for a participative action research, the main weakness of the qualitative research is how you show the results. Quantitave research offers a wide range of tools for representing results in a quick glimpse.

I use a methodology and software - Concept Systems - that is quite useful for representing qualitative research. I'm still working in a paper describing how we use the methodology, but you can read how we used it in another project. We analyze how structural policies impact to the health of populations: http://www.sciencedirect.com/science/article/pii/S1353829213000695

Thank you very much for the useful comments! It seems that combination of multiple methods always helps when it comes to policy studies.

Hello all. This is very interesting.  I did a study in Kenya on academic-policymaker networks and began with mapping the networks using sociometric surveys, then using social network analysis methods to identify key persons in the network (depending on criteria for who you are looking for in terms of "key" person) and then interviewing these persons using a qualitative approach. Interviews of academics as well as policymakers helped us understand the network structure as well as methods of engagement between the two parties. Document review, together with quant and qual analysis helped with triangulation as well as exploration of these policy networks.

I think for your study the best way to do mix methods which qualitative and quantitative. You can do interview and also you can do EGD (experts group discussion) it will be very helpful if you could get right participants. 

In my opinion Social Network Analysis is a right method for this topic

You can use SERVQUAL model. which can provide the provided materials and the expectations from consumers of what ever service is provided.

First, you should clear, what do you want to study either of content of policy or interlinking of policy with other policies. If your interest is on content of the policy, use content analysis method, if  on interlink of policy, use network analysis/social network analysis  method by incorporating secondary as well as primary information.

Actually  I am doing both in a way. My purpose is to study different network configurations within health policy sector in Turkey (at the moment I have specified 4 networks corresponding to 4 policy sub-sectors marked by different types of interaction, respective actors and linkages between them) and investigate the conditions for their emergence.  Thank you for your feedback!