Prior to developing an individualized treatment program, clinicians commonly utilize a functional analysis (e.g., Iwata et al., 1982/1994) to assess the specific function(s) of their client’s behaviors. Functional analyses can result in inconclusive outcomes when the conditions tested do not effectively replicate establishing operations relevant to the client’s behavior. To avoid this issue, researchers and clinicians have adapted the functional analysis process to incorporate idiosyncratic variables that render relevant establishing operations in an attempt to evoke target behavior. Schlichenmeyer et al. (2013) provided a review of the functional analysis literature that described how idiosyncratic variables were used to individualize the behavioral assessment. The purpose of the current project was to provide a review of the recent functional analysis literature with a specific focus on idiosyncratic environmental manipulations in functional analysis conditions throughout the past decade (2011 - 2020) and evaluate the quality and rigor of each study.