Colin VanLang

Colin is a product engineer at Sierra. Previously, he led engineering teams at Watershed, Lattice, and Dropbox. He studied Structural Engineering at Stanford University.

Posts by Colin VanLang

White text reads "Monitoring the monitor" on a blurry blue and pink background.

Who monitors the monitors?

Sierra's always-on evaluation layer use an LLM-as-judge to review every conversation so businesses can track agent quality and customer sentiment. But who evaluates the monitors?

7. Mai 2026

Text "Improving search" on a blurred green and pink background

Golden articles: Evaluating and improving search

Search evaluation shouldn’t be static — it should reflect what actually helps resolve real customer issues. By measuring performance daily against production conversations and feeding those signals back into the system, we've built a continuously improving system for resolving customers’ needs.

14. April 2026

Meet Linnaeus and Darwin: Search models that drive higher resolution rates

Our purpose-built retrieval and reranking models outperform off-the-shelf ones, driving up to 16 percentage point improvements in resolution rates.

3. April 2026

Colin VanLang

Posts by Colin VanLang

Who monitors the monitors?

Golden articles: Evaluating and improving search

Meet Linnaeus and Darwin: Search models that drive higher resolution rates

Entdecken Sie, was Sierra für Sie tun kann

Posts by Colin VanLang

Who monitors the monitors?

Golden articles: Evaluating and improving search

Meet Linnaeus and Darwin: Search models that drive higher resolution rates