Drawing on data from more than 53,000 pre-Columbian, Native American archaeological site locations, John Lambert and the Illinois State Archaeological Survey (ISAS) are using GIS-based tools, statistical analysis, and over a century of archaeological work in Illinois to build the Illinois Archaeological Predictive Model (IAPM). The goal for the free and publicly available IAPM is to help protect and preserve Illinois' archaeological resources and promote sustainable development by guiding developers to areas with a low probability of disturbing cultural resources. It is designed to be a resource for the general public, landowners, state agencies and legislators, as well as other archaeologists.

The IAPM uses known locations of sites, landforms that lack archaeological sites, and other environmental and geophysical variables such as elevation, distance to rivers and streams, and native vegetation to predict where archaeological sites may be found. Data sampled from these locations are analyzed using multilevel Bayesian logistic regression statistics to predict the probability of encountering an archaeological site in every 2-acre square across Illinois. A developer who is considering several potential sites for construction of new homes could use IAPM to see how likely each location is to contain archaeological sites. Choosing to build in places with lower likelihood will both protect cultural resources and save the developer time and money.

"The IAPM is the beginning of a new era in public archaeology. With it, the people of Illinois, and beyond, will realize the benefits of being good stewards of our shared cultural and historical resources," said Timothy Pauketat, Illinois State Archaeologist. "We are grateful to the Prairie Research Institute at the University of Illinois, and the Illinois Department of Transportation, for helping make this new era possible," Pauketat said.

"Predictive modeling is a good approach because it is cost effective and brings archaeology into the conversation sooner with developers, but it cannot replace surveys," said Lambert. ISAS sends teams of archaeologists across the state to survey locations by recording data, collecting artifacts, and in some cases, excavating. These investigations help assess the archaeological significance of locations ahead of future developments.

ISAS is incorporating predictive modeling into its project planning to help tailor survey methods and prioritize survey locations. "These models have a strong focus on practical applications and prioritize predictive accuracy," said Lambert, "As we keep collecting data across the state through future survey and excavation, the IAPM will continue improving its accuracy."

Illinois joins only a handful of states (Iowa, Minnesota, Washington, Pennsylvania, and North Carolina) to begin using archaeological predictive modeling. Minnesota was the first state to have a statewide predictive model (first released in 1998).

For more information about the IAPM, please visit:
https://www.isas.illinois.edu/office_of_the_illinois_state_archaeologist/illinois_archaeological_predictive_model