Well what's happening is it the, during the war, right, we're constraining the computer to estimate, like a single coefficient that is applicable to both war and peacetime er isn't the case, right,th there is a structural change, right, so when th when we constrain the computer to estimate the coefficients throughout the whole period, right, the coefficients are biased but if they don't apply either to the post er pre war peacetime sample neither do they er fit very well to the data during the wartime, right, if we allow the intercept to change but we're getting much better estimates both wartime and peacetime er parameter's okay because we haven't got rid of, we've got rid of that bias, right, in constraining the parameters to fit both wartime and peacetime er time periods.