This paper theorises a curriculum model containing four features. We use these features as criteria to analyse and evaluate two distinctive curriculum design types: '21st Century Learning' and 'Powerful Knowledge'. The four features are: (i) the underpinning theory of knowledge in each curriculum design type; (ii) the knowledge structures used to organise the curriculum material; (iii) the organisation of the concepts and content according to the principle of conceptual progression; and (iv) the pedagogy associated with the curriculum design, such as direct instruction or personalised learning. The distinction we make between the two curriculum design types and the comparative approach taken in the paper is justified by the differences found in each of the types with respect to all of the four features. Following the analysis of each feature in the body of the paper we judge the relative merits of each design type in terms of the logical connections between the four theorised features and the ways in which they are realised in 21st Century Learning and Powerful Knowledge respectively.