]> The statistical significance threshold for reporting matches against database sequences; the default value is 10, such that 10 matches are expected to be found merely by chance, according to the stochastic model of Karlin and Altschul (1990). If the statistical significance ascribed to a match is greater than the ExpectationThreshold, the match will not be reported. Lower Expectation thresholds are more stringent, leading to fewer chances matches being reported. Fractional values are acceptable.