One of the hardest parts of a literature review is analysing studies done by others. You must be able to evaluate the techniques used, results obtained, conclusions drawn and errors present in each study and then apply your evaluation to your topic. Below are some questions to help you start thinking about each study. For each research study you read, ask yourself:

• What is the problem or issue being addressed? Is this problem relevant to my topic? Is the problem clearly stated? Is the significance of the problem discussed (i.e., why should the reader care about this study?)
• What are the strengths and limitations of the way the author has formulated the open question? Could the open questions be approached more effectively from another perspective? Is the research primarily theoretical, experimental, interpretive, or clinical? A combination? Could the study have been better if conducted in a different framework?
• What is the author's theoretical framework (e.g., psychoanalytic, developmental, feminist)? For example, in the field of Mars geology, many authors build their papers on the idea that Mars was once a warm, wet planet, instead of the cold, dry planet we see today. Others start with the assumption that Mars has always been cold and dry. The theories to which the authors subscribe manifest themselves through their assumptions, interpretations, and conclusions. What assumptions have your authors made? And how do those assumptions affect the conclusions they draw?
• Has the author evaluated the literature relevant to the problem/issue? Does the author discuss studies that contradict their conclusions as well as those that support it?
• How effective is the study’s design? Is the method for investigating the problem appropriate? What errors does the method introduce? How accurate and valid are the measurements?
• Is the analysis of the data accurate and relevant to the research question?
• Are the conclusions validly based upon the data and analysis?
• Has the author objectively carried out the study, or only 'proved' what he already believes?
• Does this study contribute to our understanding of the problem? How is it useful to us? How does this study fit into my review? How does its problem relate to the problem I address? How will I use its conclusions, methods, or limitations to illustrate the point I am trying to make?

List adapted from the UCLA Undergraduate Science Journal Guide to Science Writing.