grangersearch: An R Package for Exhaustive Granger Causality Testing with Tidyverse Integration

Understanding causal relationships between time series variables is a fundamental problem in economics, finance, neuroscience, and many other fields. While true causality is philosophically complex and difficult to establish from observational data alone, Granger (1969) proposed a practical, testable notion of causality based on predictability: a variable X is said to "Granger-cause" another variable Y if past values of X contain information that helps predict Y beyond what is contained in past values of Y alone. Granger causality testing has found applications across diverse domains. In macroeconomics, Sims (1972) famously applied the technique to study money-income relationships, while Kraft and Kraft (1978) pioneered its use in energy economics. Financial market researchers including Hiemstra and Jones (1994) have extended the methodology to study price-volume dynamics, and neuroscientists have adapted Granger causality for brain connectivity analysis (Seth, Barrett, and Barnett 2015). The statistical foundations rest on vector autoregressive (V AR) models (Sims 1980), with comprehensive treatments available in Lütkepohl (2005) and discussions of causal interpretation in Peters, Janzing, and Schölkopf (2017). Despite its popularity, implementing Granger causality tests in R (R Core Team 2024) remains cumbersome for applied researchers.