# Context Measuring the relative location of U.S. Supreme Court justices on an ideological continuum allows us to better understand the politics of the high court. Such measures are an important building blocking of statistical models of the Supreme Court, the separation of powers system, and the judicial hierarchy. # Content The "Martin-Quinn" judicial ideology scores are estimated for every justice serving from the October 1937 term to the present. The measures are estimated using a dynamic item response theory model, allowing judicial ideology to trend smoothly through time. Since the scores are estimated from a probability model, they can be used to form other quantities of interest, such as locating the pivotal "median" justice, as all well the location of each case in the policy space. # Acknowledgements The Martin-Quinn scores were developed by Andrew D. Martin of the University of Michigan and Kevin M. Quinn of the UC Berkeley School of Law and supported by a National Science Foundation grant. The scores are based on the 2016 release of the Supreme Court Database.