Construction Standard Production Unit system(CSPU) is used for estimating the cost of public construction projects. However, It is questionable if the reliability and/or authenticity of the system is acceptable because of the lack of consistent enactment and/or revision procedures. This study identifies the major issues relative to the enactment and/or revision of CSPU system, and establishes the measures for improving the system. This study contributes to improve the authenticity of standard production unit data obtained from CSPU system. The improvement measures are established by obtaining and reflecting expert opinions from the estimating practice. The expert pool includes scholars, researchers, and practitioners who work for public institution, and public corporation.