In this paper we study a class of weighted estimands, which we define as parameters that can be expressed as weighted averages of the underlying heterogeneous treatment effects. The popular ordinary least squares (OLS), two-stage least squares (2SLS), and two-way fixed effects (TWFE) estimands...

Regressors often have heterogeneous effects in the social sciences, implying unit-specific slopes. OLS is frequently applied to these correlated coefficient models. I first show that without restrictions on the relation between slopes and regressors, OLS estimates can take any value including...

This paper uses firm level data from the World Bank Enterprise surveys conducted in 2019 and from the COVID-19 follow-up surveys conducted in 2020 in eight European countries to investigate the link between firm characteristics before the pandemic and firm survival until 2020. For the first time...

This paper studies linear time‐series regressions with many regressors. Weak exogeneity is the most used identifying assumption in time series. Weak exogeneity requires the structural error to have zero conditional expectation given present and past regressor values, allowing errors to...

The most widely used textbooks on Introductory Econometrics conflate three distinct population parameters: the population regression function (PRF), the conditional expectation function (CEF), and the causal effect. They also incorrectly suggest, and sometimes state, that the Conditional Mean...

This study examines the impact of inward foreign direct investment (FDI) on economic growth in South and Southeast Asia from 2006 to 2022, using a comprehensive panel dataset and multiple econometric techniques. The baseline estimation employs Feasible Generalized Least Squares (FGLS), with...

The total assets of the banking sector in Romania increased significantly over the past decade, from RON 364.1 billion at the end of 2014 to RON 881.7 billion at the end of 2024, according to the statistics of the National Bank of Romania (NBR). This evolution was supported by several factors,...