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Map Challenge How to Participate

All members of the Scientific Community--at all levels of experience--are invited to participate as Challengers, and/or as Assessors.

In the Challenge Phase (July 2015-Apr 2016), 27 participants created and submitted 66 reconstructions of the challenge targets using the supplied raw image data. Challengers were encouraged to perform their own movie frame alignment, frame summation, and particle picking. Alternately, they could begin with pre-aligned, summed images and/or original author-provided particle positions. For each submission, challengers filled out a questionnaire (overview) and provided the following data:

  • final unmasked map with filtering/sharpening
  • final unmasked map without filtering or sharpening
  • half-maps and mask used for FSC calculation
  • CTF, coordinates, euler angles for each particle image used in the reconstruction

In the Blinded Assessment Phase (Nov 2016-Apr 2017), six groups have contributed reports.  Following initial review period by the map committee, the challenge data and files are now publicly available (entry authorship and software suppressed) for anyone to assess. Assessment methods could include statistical analyses, resolution estimation, or coordinate model fitting. A few suggestions gathered from software developers are summarized below. The intention is to enable comparisons of the various packages available and their options in a positive spirit.  During this period, assessors are strongly encouraged to share their plans and short result summaries on this website using the Assessment Registration Form.  Assessment results will be more fully presented and discussed via a workshop (early October 2017) as well as via manuscript submissions to a Journal special issue.

EMDataResource Validation Challenges are supported by NIH National Institute of General Medical Sciences

Please send your challenge questions, comments and feedback to

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