A citation paper describing the current structure, capabilities and some future plans for the code has been published. J. Kim et al J. Phys.: Condens. Matter 30 195901 (2018), https://doi.org/10.1088/1361-648X/aab9c3. The paper is open access for the first year. The preprint is available at https://arxiv.org/abs/1802.06922. Please cite this paper when using QMCPACK.