This course intends to train every student how to critique a paper and make appropriate inference. Every week students are assigned to critique at least two papers selected by students and background knowledge is first presented by one student who selects this paper. Every student is required to fill out a critique form before the class and then discuss openly in the class. Two forms are used: One for descriptive and another one for causal studies or inferences. After this class of putting exercises on about 32 papers, every student can make appropriate inference independently.