Quantitative metrics are the result of quantitative research phase and offer exact, comparable and easily manageable data, presented in numbers. It is used to validate insights yielded by every other method of research and data gathering, as well as to verify the results of experiments and tests. Usually it is collected by analytical tool and tied to number of visitors, sessions or other exact metric of website performance. Without quantitative metrics, defining and measuring the KPIs would be impossible. All metrics can be user defined or default system metrics.