In the last 24 months, three separate practice guidelines for posttraumatic stress disorder (PTSD) have emerged from well-respected organizations that differed in the degree to which they recommend eye movement desensitization and reprocessing (EMDR) as a treatment. An international guideline was published by the International Society for Traumatic Stress Studies (ISTSS), and national guidelines were published by the American Psychological Association (APA) and the National Institute for Health Care Excellence (NICE). ISTSS reported that EMDR was effective and as potent as the best available therapies we can currently provide. NICE was more circumspect, and APA suggested other treatments had a stronger evidence base. In this review we focus on how these differences emerged and highlight the role of the time when the analysis was conducted, differences in inclusion criteria, and errors in determining appropriate measures. The 2017 APA guidelines were found to have the least validity when all these factors were considered. However, the fact that evaluating EMDR research is susceptible to such variations in methodology highlights certain research priorities that are then discussed.