The paper studies the effects of endogenous and exogenous methods in the input-output analysis on measuring the economic spillover effects. In order to analyze the spillover effect due to the increase in the demand or expenditure of a specific industry rather than the final demand such as consumption, investment, and export, which is the ultimate objective of production activities, we need to modify the baseline input-output coefficient matrix and make the industry exogenous to obtain a net economic spillover effect due to the increase in demand from the industry. If the exogenous method is not applied, the spending increase of the industry will lead to an increase in the intermediate demand for itself, and the economic spillover effect would not be properly accounted for. This study aims to investigate magnitudes of the economic spillover effects using exogenous methods along with various forms of endogenous final demands based on residential building construction. Our empirical investigation reveals that the economic spillover effects when exogenous method is not applied are higher in all cases than those when exogenous method is applied and these differences are quite significant, indicating the spillover effects can be easily misled or misrepresented. These results suggest that it is necessary to pay more attention to the model selection when analyzing the economic spillover effect using the input-output model.