This article discusses the impact of the implementation of HR sustainability practices through human resource policies on employee productivity of SMEs. Secondly, this article also discusses the results of a comparative analysis of the validity and reliability of two studies, namely pilot test and the actual research. Both analyses were conducted through an instrument used to measure the influence of human resource sustainability practice on employee productivity of SMEs through an HR policy. The instrument is based on a research model introduced by Gollan (2000), 'Model factors that influence HR sustainability'. This research does not only attempt to prove that the instrument is strong in terms of content validity (previous studies) but also in terms of construct validity, predictive validity and reliability. The analysis results show that all the variables used in the instruments have a high value of reliability and validity in both studies. In addition, this article indirectly proves that the Gollan (2000) model has empirical proof for future research. This is supported by the stakeholders and institutions theory.