From rotational to scalar invariance: Enhancing identifiability in score-driven factor models
从旋转不变性到标量不变性:提升得分驱动因子模型的可识别性
We show that, for a certain class of scaling matrices including the commonly used inverse square-root of the conditional Fisher Information, score-driven factor models are identifiable up to a multiplicative scalar constant under very mild restrictions. This result has no analogue in parameter-driven models, as it exploits the different structure of the score-driven factor dynamics. Consequently, score-driven models offer a clear advantage in terms of economic…