To write a synthesis essay, first consider the purpose of the essay, and determine how to approach the sources in such a way as to shape the scope of the essay. Formulate a thesis based on this, and develop an organizational plan that combines the sources in a well thought-out manner to make a point.
There are two types of synthesis essays: those that use explanatory synthesis, and those that use argument synthesis to prove their points. Explanatory synthesis helps readers understand a specific topic by combining various sources into a reasonably objective presentation. Argument synthesis draws on multiple sources to present the writers point of view and support that perspective with relevant facts presented in a rational manner. Argument synthesis is thus subjective in nature.
Students developing an organized plan for a synthesis essay typically use one or more approaches to persuading the reader of the validity of the essay's thesis. Examples of successful approaches include summaries, illustrations and strawman arguments. Another effective method of development is the "two reasons" approach in which a simply stated thesis is supported by ample evidence. When planning a synthesis essay, determine which of these techniques would be most effective for the thesis in question and what supplementary claims need to be supported through them.