Welcome to my web page. I am the Head of Data Science at Twitter Inc. Prior to Twitter, I was the Head of Data Science at Convoy, the Head of Research, Analytics, and Machine Learning for Connections at Amazon, and the Chief Economist and Head of Data Science at Amazon Lending. Before joining Amazon, I spent five years at the Federal Reserve Board in Washington, DC where I was a Principal Economist in the Microeconomic Surveys Section and a Senior Economist in the Consumer Research Section. Before joining the Board, I was an Assistant Professor in the Department of Consumer Science at the University of Wisconsin-Madison.