How to Use, and Not to Use, Proportionality Principle

41 Pages Posted: 26 Mar 2019 Last revised: 9 Aug 2019

See all articles by Yun-chien Chang

Yun-chien Chang

Academia Sinica - Institutum Iurisprudentiae (IIAS)

Xin Dai

Ocean University of China

Date Written: March 3, 2019


The proportionality principle is used in constitutional law and administrative law worldwide. We argue that it has been used when it should not, and when it should, inadequately used. Our major arguments are that, first, the proportionality principle is an ill-suited tool for legislative and administrative decision-making because it in essence is an incomplete form of cost-benefit analysis, as it systematically ignores certain costs and benefits. Welfare-maximizing measures as a result may fail to pass the test of proportionality analysis. Second, use of the proportionality principle for constitutional review by courts may create an undesirable ex ante effect and may fall prey to its inherent loss aversion that cannot be easily avoided through re-framing. Third, the German theorist Robert Alexy’s influential Paretian formulation of the proportionality principle makes it either toothless or fatal. Alexy’s weight formula is not useful in comparing multiple means. Fourth, the suitability test takes the form of a teleological argument, which requires a causal relation between means and ends. Hence, to appropriately conduct proportionality analysis, empirical legal studies that identify causal relationships are often required, particularly when strict scrutiny is adopted. “Is” and “ought” can and should be aligned.

Keywords: the proportionality principle, Robert Alexy, weight formula, cost-benefit analysis, difference-making facts, teleological arguments, causal inference

JEL Classification: K23

Suggested Citation

Chang, Yun-chien and Dai, Xin, How to Use, and Not to Use, Proportionality Principle (March 3, 2019). NYU Law and Economics Research Paper No. 19-10; NYU School of Law, Public Law Research Paper No. 19-32. Available at SSRN: or

Yun-chien Chang (Contact Author)

Academia Sinica - Institutum Iurisprudentiae (IIAS) ( email )

128 Academia Sinica Rd., Sec. 2
Taipei City, 11529

Xin Dai

Ocean University of China ( email )

5 Yushan Road
Qingdao, 266003

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