The proper use of Pearson's chi-square for the analysis of contingency tables is reviewed. A 1949 article by Lewis and Burke, in which they cite nine primary sources of error in the use of chi-square, serves as the basis of the review. Those nine sources of error are re-examined in light of current research. In addition, techniques and research on chi-square published after 1949 are discussed. Emphasis is placed on techniques which are of use to the practical researcher in education who often deals with qualitative ordered and unordered data. (Author/GK)