In this paper, we develop a novel formalization of Fuzzy Trace Theory (FTT), a leading theory of qualitative risky decision-making. Our model is the first to explicitly formalize and integrate the concepts of gist and the gist hierarchy. Domain knowledge constrains the space of possible decision problems, explaining which gists are chosen in which contexts. We test our model against risky-choice framing and Allais paradox problems, and manipulations of these problems. Our results also confirm new predictions regarding how problem manipulations can enhance or attenuate framing effects.