Christina Göpfert

Christina Göpfert

Applied Scientist, Machine Learning

Amazon

Biography

I am a practical ML scientist with a strong theoretical foundation. My PhD and research at DeepMind, Google Brain, and Google Research gave me deep expertise in learning theory, robustness, and interpretability. At Amazon, I apply that rigor to real-world problems: causal evaluation, auction design, and shipping models at scale.

Interests

  • Robustness
  • Learning Theory
  • Interpretability
  • Causal Evaluation
  • Auction Design

Education

  • PhD in Machine Learning, summa cum laude, 2015-2022

    Bielefeld University

  • MSc in Mathematics, grade 1.0, 2013-2015

    Bielefeld University

  • BSc in Mathematics & Computer Science, grade 1.1, 2010-2013

    Bielefeld University

Experience

 
 
 
 
 

Applied Scientist

Amazon DSP, Auction Team

Oct 2022 – Present Berlin, Germany
  • Developed a bidshading algorithm for bid price optimization, achieving a 4.3% total surplus improvement in online experiments.
  • Built an offline auction simulation system with counterfactual evaluation to pre-screen parameter changes before online experiments.
  • Designed a bandit-based approach for automated auction parameter tuning via best-arm identification.
  • Trained and launched ML models serving all off-Amazon Sponsored Display traffic.
 
 
 
 
 

Research Intern

DeepMind

Aug 2021 – Dec 2021 Remote (London)
  • Investigated leave-one-out stability of SGD outcomes in neural networks from a learning theory perspective.
  • Designed and ran experiments training shallow networks in JAX to empirically bound leave-one-out variability.
  • Found that intrinsic stochasticity of GPU floating-point arithmetic provides a significant lower bound on outcome variability.
 
 
 
 
 

Research Intern

Google Research

Jun 2020 – Sep 2020 Remote (Mountain View)
  • Built an interpretable semantic layer on top of a two-tower recommender to capture personalized soft-attribute preferences from natural language feedback.
  • Owned data analysis, model design, training, and experimental evaluation end to end.
  • Published in ACM Transactions on Recommender Systems.
 
 
 
 
 

Research Intern

Google Brain

Sep 2018 – Dec 2018 Zurich, Switzerland
  • Characterized conditions under which semi-supervised learning improves upon minimax rates of the supervised setting.
  • Published at the Conference on Learning Theory (COLT).