Purpose: The fundamental aim of this article is to verify an assumption according to which the
proper Regulatory Impact Assessment (RIA) is a key factor in the rationality of law. Rational law
is a law which is effective and able to realize and achieve social, economic and environmental aims
determined and established by the lawmaker.
Methodology: The scope of this paper – which determines its structure – encompasses the definition
of RIA, including its specific (but non-legal) forms such as benchmarking and evaluation. As
far as we are concerned, these methods can provide – as a kind of Regulatory Impact Assessment
– a significant tool for measuring the rationality of regulations. Furthermore, the usefulness of
benchmarking and evaluation has been recognised by representatives of jurisprudence. We will
also explain the concept and the assumptions of the rationality of law on the grounds and in the
light of the case law of the Polish Constitutional Tribunal and the Supreme Administrative Court.
This should allow to countercheck the main thesis of this paper. The methodology encompasses
primary legal methods such as literature, case law and legislation analysis.
Findings: An indispensable condition of the rationality of law is actual elimination of irrational
regulations which were not subjected to the Regulatory Impact Assessment.
Practical implications: Although RIA is a problematic issue (in terms of its practical application),
it is necessary to carry it out in order to assure the rationality of law. A good and desirable complement
to Regulatory Impact Assessment are non-legal methods such as benchmarking and evaluation.
Originality: Originality and value of this survey lies in taking into account the case law of the
Polish Constitutional Tribunal and the Supreme Administrative Court. Additionally, this paper is
original in that it considers non-legal methods in the examination of the rationality of law.