Multiple discriminant analysis was used to analyze the structure of a perceived environmental uncertainty variable employed previously in research on public relations roles. Data came from a subset (N=229) of a national sample of public relations practitioners belonging to the Public Relations Society of America, who completed a set of scaled items measuring the simple-complex dimension (the number of factors perceived as relevant to decision-making behavior) and static-dynamic dimension (the degree to which these important factors are seen as stable) of the work environment. An additional question was used to break down the sample into four role model categories: (1) expert, (2) technical services provider, (3) communication process facilitator, and (4) problem solving process facilitator. Overall, it was shown that the multiple discriminant analysis technique unearthed a hitherto hidden dimension of "threat" in the public relations practitioner's environment. The static-dynamic dimension, although altered by the analysis, appeared to be valid for describing this environment. Practitioners did not seem to evaluate their environments along the simple-complex dimension. (FL)