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Xavier Moreno

Xavier Moreno

AI Systems Specialist - Machine Learning Evaluation

USA flag
Arizona, Usa
$40.00/hrExpertData Annotation Tech

Key Skills

Software

Data Annotation TechData Annotation Tech

Top Subject Matter

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Computer Code ProgrammingComputer Code Programming
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Top Label Types

Classification
Computer Programming Coding
Transcription

Freelancer Overview

I have over eight years of experience specializing in AI model evaluation, data annotation, and the development of high-quality training data for machine learning systems. My background includes hands-on roles at Scale AI, Appen, and Lionbridge (now TELUS International AI), where I evaluated language models, validated backend-driven outputs, and refined data labeling guidelines to ensure consistency and accuracy. I am skilled in Python, statistical analysis, and rubric-based scoring systems, with a strong understanding of NLP, LLMs, and backend data pipelines. I excel at collaborating with engineers and researchers to translate qualitative feedback into quantifiable improvements, and I am committed to delivering reliable, reproducible evaluation artifacts that meet production-grade standards. My work has helped optimize model performance, reduce variance, and support iterative deployment in fast-paced, real-world environments.

ExpertEnglish

Labeling Experience

Data Annotation Tech

Data Labeling & Human Feedback Specialist

Data Annotation TechImageClassification
Labeled and curated high-quality training data for large-scale machine learning models, including NLP and reasoning-focused tasks used in production AI systems. Applied detailed annotation guidelines to produce consistent, low-noise labels across complex, ambiguous inputs. Participated in iterative guideline refinement to reduce variance, bias, and ambiguity in labeled datasets. Conducted quality audits and disagreement analysis to identify systematic labeling errors and edge cases impacting downstream model performance. Collaborated with researchers and project leads to translate qualitative human judgments into structured signals suitable for model training and evaluation. Supported active learning and feedback loops by prioritizing difficult or high-impact examples for annotation.

Labeled and curated high-quality training data for large-scale machine learning models, including NLP and reasoning-focused tasks used in production AI systems. Applied detailed annotation guidelines to produce consistent, low-noise labels across complex, ambiguous inputs. Participated in iterative guideline refinement to reduce variance, bias, and ambiguity in labeled datasets. Conducted quality audits and disagreement analysis to identify systematic labeling errors and edge cases impacting downstream model performance. Collaborated with researchers and project leads to translate qualitative human judgments into structured signals suitable for model training and evaluation. Supported active learning and feedback loops by prioritizing difficult or high-impact examples for annotation.

2020 - 2021

Education

C

Columbia University

Master of Science, Data Science

Master of Science
2021 - 2021
U

University of California, San Diego

Bachelor of Science, Computer Science

Bachelor of Science
2017 - 2017

Work History

S

Scale AI

AI Response Evaluator / Quality Analyst

Arizona
2024 - 2025
S

Scale AI

Language & Model Evaluation Specialist

Arizona
2021 - 2023