RScriptForExchangeRateAnalysis/README.md

ECB FX Trend Analyzer & Pair Ranker

Overview

This R script automates the extraction and statistical analysis of daily foreign exchange rates from the European Central Bank (ECB). Designed for trend-following or long/short strategy research, it identifies the top FX pairs exhibiting the strongest, most predictable linear trends over a customizable rolling window.

Instead of relying on standard return/volatility metrics, it ranks pairs using a custom Signal-to-Noise Ratio derived from linear regression, isolating pairs that move cleanly in one direction with minimal chop.

---

Key Features

• Automated Data Ingestion: Securely downloads, unzips, and cleans the latest historical daily exchange rate dataset directly from the ECB repository.
• Dynamic Cross-Pair Generation: Automatically calculates non-EUR cross-pairs (e.g., USD/JPY, GBP/JPY) on the fly based on any user-defined list of target currencies.
• Custom Timeframes: Allows users to easily slice the dataset to analyze specific lookback periods (e.g., the last 720 days).
• Statistical Ranking Methodology: * Runs a simple linear regression for each currency pair (Exchange Rate ~ Time).
  • Extracts the slope (Beta) to measure the strength and direction of the trend.
  • Extracts the Residual Standard Error (RSE) to measure the volatility or "noise" around that trendline.
  • Ranks all pairs by |Beta| / RSE, surfacing the top 3 pairs with the smoothest, most predictable trajectories regardless of whether they are trending up or down.

---

Prerequisites

• R (Version 3.0 or higher): The script relies entirely on base R functions. No external libraries (like dplyr or quantmod) are required.
• Internet Connection: Required for the script to automatically fetch the latest dataset directly from the ECB servers.

---

How to Use

1. Open the Script Open the .R file in your preferred environment (RStudio, VS Code, or the standard R GUI).

2. Configure Your Parameters At the very top of the script, locate the CONFIGURATION section to customize your analysis:

• target_currencies: An array of the currency tickers you want to analyze. The script will automatically generate all possible cross-pairs from this list. (Note: All original columns are priced with a EUR base by default).
• n_days_to_analyze: An integer representing your lookback window in days (e.g., 720 for roughly two years). Set this to NULL to analyze the entire historical dataset dating back to 1999.

# Example Configuration
target_currencies <- c("USD", "JPY", "GBP")
n_days_to_analyze <- 720