Robert Engle is an American economist known for his work in the field of econometrics, particularly in the analysis of time series data. He was awarded the Nobel Prize in Economic Sciences in 2003 for developing the ARCH model (Autoregressive Conditional Heteroskedasticity), which helps in understanding and predicting financial market volatility. Engle's research has significantly influenced how economists and financial analysts assess risk and make decisions based on fluctuating data. His contributions have been widely applied in various fields, including finance, economics, and statistics, making him a prominent figure in modern economic theory.