def METHOD_NAME(self):
    size_reduction = OrderedDict()
    for p in self.patient_identifiers:
        props = self.load_properties_of_cropped(p)
        shape_before_crop = props["original_size_of_raw_data"]
        shape_after_crop = props['size_after_cropping']
        size_red = np.prod(shape_after_crop) / np.prod(shape_before_crop)
        size_reduction[p] = size_red
    return size_reduction