... can take the exposure at default to be the dependent variable and several independent variables like customer level characteristics, credit history, type of loan, mortgage, etc. When we want to study the properties of the obtained estimators, it is convenient to distinguish between two categories of properties: i) the small (or finite) sample properties, which are valid whatever the sample size, and ii) the asymptotic properties, which are associated with large samples, i.e., when tends to . 2. minimum variance among all ubiased estimators. Relative e ciency: If ^ 1 and ^ 2 are both unbiased estimators of a parameter we say that ^ 1 is relatively more e cient if var(^ 1)