What are archaeology's biggest scientific challenges?

This is posted on behalf of Keith Kintigh and others, listed below, working on a project to identify “Grand Challenges” in archaeology.

We invite your participation in an effort to identify “grand challenge” problems in archaeology. This confidential survey is a key component of a research project that will compile and publish a list of “grand challenge” problems in archaeology and develop an associated plan that would justify major US National Science Foundation (NSF) investments in computational infrastructure for archaeology.  To participate, please go to:
Professional archaeologists and archaeology graduate students are invited to contribute. The important questions don’t have national boundaries and we want to include a broad spectrum of professional voices, including those outside the US.  Please feel free to forward this request to other interested individuals.  Participation is voluntary but you must be at least 18.  The survey takes only 2-10 minutes. For additional information you may follow the link or contact Keith Kintigh (principal investigator; kintigh@asu.edu).  We thank you in advance for your assistance.  
Keith Kintigh, Arizona State University
Jeffrey Altschul, Statistical Research, Inc. & SRI Foundation
Ann Kinzig, Arizona State University
W. Fredrick Limp, University of Arkansas
William Michener, University of New Mexico
Jeremy Sabloff, Santa Fe Institute