Before revision:  We propose a novel form of scale normalization on an arbitrary interquantile range, which  proves particularly convenient for characterizing the identification relationships in our model , as quantiles provide direct linkages between the observable conditional probabilities and the unknown index values.
After revision:  We propose a novel form of scale normalization on an arbitrary interquantile range, which proves particularly convenient for the identification analysis , as quantiles provide direct linkages between the observable conditional probabilities and the unknown index values.