 The results of this study suggest that the X-ray diffraction technique is the best method for measuring the crystallinity of cellulose, as it produces the highest accuracy when compared to other methods. However, the crystallinity index does not necessarily indicate the digestibility of cellulose, as there are many other factors that can affect the process. Therefore, caution must be taken when correlating small changes in crystallinity with large changes in cellulose digestibility. This article was authored by Perilla Philippe, Himmel Michael E., Baker John O., and others.