Causality is a complex concept, which roots its developments across several fields, such as
statistics, economics, epidemiology, computer science, and philosophy. In recent years, the …

External validity captures the extent to which inferences drawn from a given study's sample
apply to a broader population or other target populations. Social scientists frequently invoke …

This paper synthesizes recent advances in the econometrics of difference-in-differences
(DiD) and provides concrete recommendations for practitioners. We begin by articulating a …

Abstract The Carbon Emission Trading Scheme is generally considered an important market-
oriented environmental policy tool aiming at carbon abatement. Therefore, the government …

As the second-largest economy in the world with both high-energy consumption and high‑
carbon emission, China has launched several green finance pilot zones (GFPZ) targeting …

The Effect: An Introduction to Research Design and Causality is about research design,
specifically concerning research that uses observational data to make a causal inference. It …

Background The Medical Research Council published the second edition of its framework in
2006 on developing and evaluating complex interventions. Since then, there have been …

Probably because of their interpretability and transparent nature, synthetic controls have
become widely applied in empirical research in economics and the social sciences. This …

Background Mandatory COVID-19 certification (showing vaccination, recent negative test, or
proof of recovery) has been introduced in some countries. We aimed to investigate the effect …

We use the synthetic control method to analyze the effect of face masks on the spread of
COVID-19 in Germany. Our identification approach exploits regional variation in the point in …