Chen, Qiang; Li, Wenjun - In: Journal of applied economics 27 (2024) 1, pp. 1-20
control units are often sparse. But the sparsity of SCM has received little attention in the literature except Abadie (2021 …), which explores the sparsity from the perspective of predictor space. In this paper, we make three contributions. First, we …. Second, we offer a simple alternative explanation about the sparsity of SCM from the perspective of parameter space. Third …
