This paper presents a cognitive study that evaluates design creativity in parametric design environments, in relation to more conventional geometric modelling environments. The study correlates the results of design outcome evaluations and design process analysis. To achieve this comparison, a combined method of jury evaluation and protocol analysis is adopted. Firstly, eight professional architects were asked to complete two architectural design tasks with similar complexity, respectively in a parametric design environment and a geometric modelling environment. Following the design experiment, 19 experts were then invited to evaluate the design outcomes produced by designers using pre-defined criteria focusing on design creativity. The creativity evaluation criteria address concerns related to innovation, usefulness, and unexpectedness. Outcomes of the evaluation and comparison are correlated to findings of a series of protocol studies on related parametric design processes. Results of this study suggest that parametric design potentially enhances overall design creativity from various perspectives.