Reports of novel organic polymeric flocculants have become commonplace. The method used to test the effectiveness of these flocculants is most often the flocculation of a kaolin suspension in a jar test. The widely varying versions of this method that appear in the literature suffer from a range of weaknesses. The present research uses well-defined kaolin and confines testing to conditions in which the kaolin suspension is stable in the absence of a flocculant. The research examines all aspects of the conduct of the method, including clay dosing, mixing, settling time, and measurement to improve the sensitivity, reproducibility, and robustness of the method, and takes steps to avoid pitfalls that can reduce the validity of the method. Innovations include careful selection of the buffer system and instrument characteristics. Kaolin Clarification Effectiveness is introduced as a metric that gives a meaningful indication of the relative value of a novel flocculant while emphasizing the critical importance of test conditions. Together, the results form a set of recommended test conditions that should be useful for new flocculant research.