That is why it was so crucial that Sewall Wright distinguished path coefficients (which represent causal effects) from regression coefficients (which represent trends of data points). Path coefficients are fundamentally different from regression coefficients, although they can often be computed from the latter. Wright failed to realize, however, as did all path analysts and econometricians after him, that his computations were unnecessarily complicated. He could have gotten the path coefficients from partial correlation coefficients, if only he had known that the proper set of adjusting
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