Multicollinearity and Parameter Estimation in Simultaneous‐Equation Models of Fluvial Systems

Abstract

Simultaneous‐equation statistical models are an attractive method for directly analyzing interactions among components of geomorphic systems. This study demonstrates that the utility of simultaneous‐equation analysis is limited for fluvial systems by inherent multicollinearity among hydrologic and morphologic variables. Although multicollinearity for observed data may not be severe, estimation procedures for simultaneous‐equation models often enhance this multicollinearity to problematic levels. Diagnostic tests are applied to three models of fluvial systems to illustrate the severity of the problem. It is recommended that investigators who develop simultaneous‐equation models perform appropriate diagnostic evaluations to determine the impact of multicollinearity on specific parameter estimates. 1991 The Ohio State University