Correlates of State PolicyThe Correlates of State Policy Project includes more than seven-hundred variables, with observations across the U.S. 50 states and time (1900 – 2016). These variables represent policy outputs or political, social, or economic factors that may influence policy differences across the states. The codebook includes the variable name, a short description of the variable, the variable time frame, a longer description of the variable, and the variable source(s) and notes.