Files and metadata associated with the EMDataBank/Unified Data Resource for 3DEM 2015/2016 Map Challenge hosted at challenges.emdatabank.org are deposited. All members of the Scientific Community--at all levels of experience--were invited to participate as Challengers, and/or as Assessors. Seven benchmark raw image datasets were selected for the challenge. Six are selected from recently described single particle structure determinations with image data collected as multi-frame movies; one is based on simulated (in silico) images. All of the raw image datasets are archived at pdbe.org/empiar. 27 Challengers created 66 single particle reconstructions from the targets, and then uploaded their results with associated details. 15 of the reconstructions were calculated using the SDSC Gordon supercomputer. This map challenge was one of two community-wide challenges sponsored by EMDataBank in 2015/2016 to critically evaluate 3DEM methods that are coming into use, with the ultimate goal of developing validation criteria associated with every 3DEM map and map-derived model.

{"references": ["Henderson et al (2012) Outcome of the first electron microscopy validation task force meeting. doi:10.1016/j.str.2011.12.014", "Lawson et al (2016) EMDataBank unified data resource for 3DEM. doi:10.1093/nar/gkv1126", "Marabini et al (2016) The Electron Microscopy Exchange (EMX) Iniitiative doi:10.1016/j.jsb.2016.02.008"]}

The 2015/2016 Map Challenge was supported by the US National Institutes of Health / National Institute for General Medical Sciences (NIH/NIGMS) Under Grant Number R01 GM079429 to Wah Chiu (PI). A Directors Award from the UCSD Supercomputer Center provided supercomputer access that was used in 15 of the 66 submitted entries.