Somewhat related to my work on social cost. Here is the abstract:

More than one hundred years ago, the U.S. Supreme Court started to refer to social science evidence in its judgments. However, this has not resonated with many constitutional courts outside the United States, in particular in continental Europe. This contribution has a twofold aim. First, it tries to show that legal reasoning in constitutional law is often based on empirical assumptions so that there is a strong need for the use of social sciences. However, constitutional courts often lack the necessary expertise to deal with empirical questions. Therefore, I will discuss three potential strategies to make use of social science evidence. Judges can interpret social facts on their own, they can afford a margin of appreciation to the legislator, or they can defer the question to social science experts. It will be argued that none of these strategies is satisfactory so that courts will have to employ a combination of different strategies. In order to illustrate the argument, I will discuss decisions of different jurisdictions, including the United States, Canada, Germany and South Africa.

From the article:

The discussion on the role of social sciences in constitutional adjudication has a long history. More than one hundred years ago, the U.S. Supreme Court acknowledged that social science ev- idence can play a significant role in the interpretation of the constitution.1 In Muller v. Oregon, the Court had to decide whether labor regulation for the protection of women violated the due process clause of the Fourteenth Amendment of the U.S. Constitution.2 It based its argument on social science evidence showing that women were in need of labor protection and concluded that the legislature had a rational basis for enacting the statute. Nearly half a century later, the Su- preme Court used social science evidence at the heart of another groundbreaking decision. In Brown v. Board of Education, the Court used psychological evidence to establish that the racial segregation of schools caused psychological harm to black students and thus violated the Equal Protection Clause of the Fourteenth Amendment.3

However, this long history of the use of social science evidence in U.S. constitutional law has not resonated with many other constitutional courts. In particular in continental constitutional adjudication, social science approaches play a marginal role. Although economic thinking has some influence on the scholarship in private or antitrust law on the European continent,4 the same development cannot be observed in the realm of constitutional law.5 There are probably two principal reasons for this observation. On the one hand, the most popular social science ap- proach in legal scholarship is the economic analysis of law. This economic analysis is often based on micro-economic theory, which deals with the interaction of individuals. Constitutional law often deals with societal phenomena that are considerably broader and for which the toolkit of micro-economic theory often does not fit. …

This contribution will draw on examples from four different jurisdictions in order to show the necessity, but also to highlight the difficulties of using social sciences in constitutional adjudica- tion. I have chosen two jurisdictions, which are rather reluctant to deal with social sciences – Germany and South Africa –, as well as two, the Canadian and the US American, where the so- cial science implications of constitutional decisions are commonly discussed and reflected. The argument of this contribution will be unfolded in two steps. The first part will demonstrate that normative arguments are often based on implicit empirical assumptions. It will illustrate that constitutional courts often avoid to second-guess these empirical assumptions, although they are indispensable elements of their argument. The second part will compare three different strategies of constitutional courts to deal with the empirical implications of their decisions: courts can con- cede a margin of appreciation to the legislator, they can defer the empirical questions of their decisions to expert witnesses, or they can answer the empirical questions themselves. However, it is argued that each of these strategies has serious shortcomings. Therefore, courts need to combine different strategies.