modified results. This study found that when controlling for number of employees, the effect of having two or more publications does not entirely go away, it was just less robust. Therefore, Hypothesis 3 is slightly supported because the effects do not completely cease to exist regardless of the type of sensitivity analyses performed.
LIMITATIONS AND IMPLICATIONS FOR FUTURE RESEARCH The most obvious limitation of this study was the difficulty of collecting information on private companies. About 10% of orphan drug sponsors and 29% of nonorphan drug sponsors in my sample were public companies, and thus information on company size and the measures relating to my independent variables were more readily available. The lack of access to private company data, especially in regards to PRO formal ties, disabled this study from providing a complete analysis of the relationship between an organization’s public sector engagement and the likelihood of participating in the ODA. No conclusions could be drawn with respect to Hypothesis 2 due to the large number of missing cases for PRO formal ties. A valuable investigation for future investigation would be to address this hypothesis by devising alternative ways to gather information on company ties to PROs, aside from extracting information from SEC filings. Another significant challenge was related to the independent variables. While these variables were selected as best representative of a firm’s public sector engagement, there are other factors to consider which would provide an additional dimension to the study. Future research should therefore be directed at collecting different measures also
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