We present a careful analysis of possible issues of the application of the self-excited Hawkes process to high-frequency financial data and carefully analyze a set of effects that lead to significant biases in the estimation of the "criticality index'' n that quantifies the degree of endogeneity...

This study examined social system failures and sought to identify a plausible mechanism behind these failures. Stretched exponential distributions were observed for failure of marriages in the US, UK, and Germany. In addition, the study provides evidence of power laws in the failure of large...