VPIN Volume Synchronized Probability
Easley et al.  proposed a high-frequency estimate of PIN, which they named volume-synchronized probability of informed trading (VPIN). This procedure adopts a volume clock, which synchronizes the data sampling with market activity.
For additional details and case studies of VPIN, see Easley et al. .
A number of studies have found that VPIN indeed has predictive power: Abad and Yague , Bethel et al. , Cheung et al. , Kim et al. , Song et al. , Van Ness et al. , and Wei et al. , to cite a few.
This indicator is based on Advances in Financial Machine Learning 2018 - Marcos Lopez de Prado book, Page 292.