Fang's research interests include studying the antimicrobial activity of reactive nitrogen and oxygen species against Salmonella enterica and Staphylococcus aureus. His laboratory also discovered the process of xenogeneic silencing, whereby bacteria incorporate foreign DNA into regulatory pathways.[1] He became interested in studying scientific retractions after he retracted six papers that had been published in Infection and Immunity. He subsequently began studying the subject in more detail with another of the journal's editors, Arturo Casadevall. They published a paper on the subject in 2011, in which they coined the term "retraction index".[7] He has also catalogued the incidence of scientific fraud, and published a study in 2012 finding that such fraud has become increasingly common in recent years.[8][9][10] In 2014, he co-authored another study showing that every paper retracted because of scientific misconduct costs the National Institutes of Health about $400,000 on average.[11] In 2023, he and Casadevall published "Thinking About Science: Good Science, Bad Science, and How to Make It Better" (ASM/Wiley), a collection of essays.