In Chaos, researchers explore the factors driving background checks, and whether coordination between U.S. states may exist and if one state exerts influence over others in terms of enacting gun laws or acquiring firearms. They researchers constructed a rigorous mathematical approach to interpret the patterning of firearm background check data and found these patterns of frequency oscillations are different at various time points. This suggests states may have interacted differently with each other during the terms of Bush, Obama, and Trump.