“…Second, since there are now only J − 1 logged ratio series, s t j , we can include each of them as dependent variables in a system of equations, which gets around the redundant degree of freedom problem. A system of equations approach also provides the ability to take into account the correlated error structure across time, as explicitly modeled using methods such as SUR or VAR models (Brandt, Monroe, and Williams, 1999;Jackson, 2002;Mikhailov, Niemi, and Weimer, 2002;Basinger, Cann, and Ensley, 2012;Philips, Rutherford, and Whitten, 2016a). 7…”