“…Several variance reduction methods have been proposed for this problem. Among the most prominent ones, we find conditional Monte Carlo approaches (Cancela and El Khadiri, 2003;Cancela et al, 2009b;Elperin et al, 1991;Gertsbakh and Shpungin, 2010;Lomonosov and Shpungin, 1999), methods that change the sampling distribution (usually by concentrating the sampling in subsets of the sample space where there is more uncertainty, using paths and cuts to determine those subsets) (Fishman, 1986;Manzi et al, 2001;Zenklusen and Laumanns, 2011), approximate zero-variance importance sampling (L'Ecuyer et al, 2011), and combinations of those (Cancela et al, 2010). There are many more.…”