The primary difference between the Delphi method and the modified nominal group technique is in the anonymity of the Delphi method vs. the group consensus of the modified nominal group technique. Whereas both are listed as iterative processes that seek out methods to solve phenomena, the modified nominal group technique utilizes learner surveys and focus groups.
In the Delphi Method, “It is appropriate for researching complex issues where larger scale quantitative "hard data" fails to unearth richness in tacit knowledge to help the research understand subtle expert opinion. It does not offer the rigor of clinical testing or quantitative analysis, but it provides a scientific methodology that is well suited to issues that require the insights of subject matter experts.”(Thomas 2009)
According to Kuo-Hung, a nominal group technique (NGT) can be used for knowledge transfer and internalization of knowledge in the consensus building process if an information platform was successfully designed and tested. (Kuo-Hung, Shi-Jer et al. 2006)
I believe that my position would be to utilize the Delphi closed collaboration research method for the simple reason that my innovation is simply that, mine. I would seek out the data needed to prove my phenomenon and open collaboration would not be needed.
Kuo-Hung, T., L. Shi-Jer, et al. (2006). "Using Online Nominal Group Technique to Implement Knowledge Transfer." Journal of Engineering Education 95(4): 335-345.
Thomas, G. (2009). "The Delphi technique: a method for testing complex and multifaceted topics." International Journal of Managing Projects in Business 2(1): 112-130.