Design synthesis is an abductive reasoning process from abstract intents to concrete instantiations under
constraints. This process involves two stages: purposeful "alternative creation" and systematic "alternative
selection". This paper presents a synthesis framework to support decision making during these two phases
for early-stage innovative design. For alternative creation, a decision process that uses three synthesis
reasoning operations to generate innovative options is provided. For alternative selection, an aggregation
method that combines multiple preferences to choose the most preferred option is developed. This decision
framework can be seen as a theoretical generalization of the Axiomatic Design Theory to better support
design synthesis.