Unobservable effects and firm's capital structure determinants

Purpose – This paper aims to test the significance of unobservable firm-specific effects on a capital structure model. Design/methodology/approach – The paper employs the restricted least squares method to test the significance of unobservable firm-specific effects in a fixed effects model that includes unobservable effects against a pooled ordinary least squares model that excludes unobservable effects. Findings – The empirical findings indicate that models that include unobservable firm-specific effects are correctly specified. Research limitations/implications – The limitation of this study comes from lack of data to measure unobservable effects such as managerial ability or managerial skills. Future research can develop index measures of managerial ability or managerial skills and borrow from management theory to explain the connection between managerial ability or managerial skills and firms' capital structure. Practical implications – The findings imply that a capital structure model that excludes firm-specific effects could be mis-specified because such a model does not control for unobservable firm-specific factors such as managerial ability or managerial skills which have significant effects on firms' capital structure decisions. Originality/value – The findings are important because the paper applies the restricted least squares method to test the significance of unobservable firm-specific effects. This technique has not been applied previously. The paper contributes to capital structure research in the fast growing South Africa.