The four-day school week (4dsw) is growing in popularity, especially in rural areas across the western United States. RAND Corporation researchers addressed knowledge gaps about the 4dsw by conducting a large-scale study of the implementation and outcomes of the 4dsw that involved the collection of original data in numerous districts across Idaho, New Mexico, and Oklahoma, as well as administrative data from these and other states. The researchers analyzed both qualitative and quantitative data to compare the 4dsw and five-day school week (5dsw). The analyses resulted in mixed findings. This appendix provides supplementary information on the implementation and outcomes of the four-day school week (4dsw) using quantitative and qualitative data from a variety of sources. The 4dsw is compared with the five-day school week (5dsw). [For the full report, see ED615237. For the Research Brief, see ED615238.]