This document summarizes discussions from a workshop organized by the National Institute of Standards and Technology's (NIST) Big Data Public Working Group. The workshop included four panels that discussed: 1) the current state of big data technologies; 2) future trends in big data hardware, computing models, analytics and measurement; 3) methods for improving big data sharing and collaboration; and 4) security and privacy concerns with big data. The panels featured presentations on topics such as big data reference architectures, use cases, benchmarks, data consistency issues, and approaches for enabling secure big data applications while preserving privacy.