Typically, automatic Question Answering (QA) approaches use the question in its entirety in the search for potential answers. We argue that decomposing complex factoid questions into separate facts about their answers is beneficial to QA, since an answer candidate with support coming from multiple independent facts is more likely to be the correct one. We broadly categorize decomposable questions as parallel or nested, and we present a novel question decomposition framework for enhancing the ability of single-shot QA systems to answer complex factoid questions. Essential to the framework are components for decomposition recognition, question rewriting, and candidate answer synthesis and re-ranking. We discuss the interplay among these, with particular emphasis on decomposition recognition, a process which, we argue, can be sufficiently informed by lexico-syntactic features alone. We validate our approach to decomposition by implementing the framework on top of IBM Watson TM , a state-of-the-art QA system, and showing a statistically significant improvement over its accuracy.Questions like these are found in domains such as medical, legal, financial, etc. Independent of domain and type, however, they share a common characteristic: If a search query is constructed from all the facts collectively describing the answer, very few (if any) relevant documents are likely to be found, with undesired consequences for the identification of potential answer-bearing passages. The notion of decomposition thus goes hand in hand with that of recursively applying a QA system to the individual facts (sub-questions), followed by suitable re-composition of the candidate answer lists for the sub-questions.Some of our earlier decomposition works were motivated by such considerations: Kalyanpur et al. (2011) offer a brief overview of the decomposition framework, within which we then discuss particular heuristics for recognizing decomposable questions .This paper presents, in depth, our evolved decomposition approach. We describe the framework, and how it relates to a class of generic QA architectures. We follow