In June, 1920, the National Intelligence Tests, Scales A and B, Form 1, were given to all the pupils between the ages of eight and fifteen inclusive, who were present on certain days in the public schools of Vallejo, California. They were given by Dr. Terman, Superintendent A. C. Barker, and four members of the school force who had had experience in giving group tests. The scoring and tabulating were done by university students and high-school seniors who were paid for their time. Their work was carefully supervised by Miss Whitmire, but sufficient funds were not avail able to have the papers scored twice. All computations were carefully checked. In all cases Scale A was given before Scale B. In about half the classes of grades v to vm both scales were given at a single sittings broken only by a rest of five to ten minutes. This was recognized as undesirable but was unavoidable because the tests were made during the last week of the school year. In the other classes Scale B followed one day after Scale A. Giving both scales at a single sitting does not, of course, affect the norms thus secured for the scale given first (Scale A), nor do we believe that it affected appreciably the norms for Scale B. It could only do so by making the norms too high (effect of practice) or too low (the effect of fatigue). In this case, since the tests of Scale B differ in kind considerably from those of Scale A, fatigue effects would ordinarily be expected to outweigh the practice effects. Whether they did so to any considerable extent,can be answered by comparing for each grade and each age separately the ratio of the Scale B norm to the Scale A norm in our own data with the corresponding ratios secured at Washington and Pittsburgh, where in all cases Scale B followed Scale A by one day. These ratios are shown in Tables I and II. It will be seen that on the