"In a [literature] review organized thematically, you group and discuss your sources in terms of the themes, theoretical concepts, and topics that either you decide are important to understanding your topic or that you have identified from reviewing the key studies on your topic. This structure is considered stronger than the chronological organization because you define the theories, constructs, categories, or themes that are important to your research. ... In these types of reviews, you explain why certain information is treated together, and your headings define your unique organization of the topic. The sequence of the concepts or themes should be from broad to specific."
(Sally Jensen, 09 September 2013)