Snorkel’s “Trusted Scale” philosophy

Welcome to Part 4 of Snorkel AI’s rubric series. In previous posts, we explored how rubrics enable structured evaluation (Part 1), the spectrum of rubric types and use cases (Part 2), and the science behind designing and validating them (Part 3). In this latest installment, we pull back the curtain on how Snorkel puts these principles into practice—our internal process for building, validating, and scaling rubrics that power trustworthy AI data pipelines.

At Snorkel AI, we operate on a core belief: quality at scale is not a contradiction, but a discipline. Data quality cannot be an afterthought—it must be designed into every stage of the process. Our “Trusted Scale” philosophy balances two priorities that often appear in tension: rigorous quality assurance and operational efficiency. By embedding rubric-based evaluation into our workflows, we enable teams to scale confidently, knowing that their datasets are both reliable and fit for purpose.

This principle gives us a competitive edge. Rather than treating quality checks as one-off audits, we systematize evaluation, turning subjective judgments into structured, repeatable metrics. That structured approach allows us to both differentiate dataset quality and measure return on investment (ROI), ensuring clients can track the impact of high-quality data on downstream model performance.

Snorkel’s quality process

To make rubric-based evaluation practical at scale, we’ve refined a multi-stage quality pipeline. Each stage builds on the previous, with rubrics serving as the connective tissue:

Figure 1. Snorkel’s quality process—from defining requirements to scaling continuous feedback.
  1. Annotation guidelines & requirements discovery
    Every project begins with careful scoping to:
    • Collaborate with clients to understand where and how the data will be used.
    • Define what “high quality” looks like in their domain and which failure modes matter most.
    • Use these insights to shape the initial rubric design—a living model refined through real-world feedback.
  1. Collaborative rubric design
    Our research and data teams co-develop rubrics in partnership with domain experts to:
    • Ensure rubrics are interpretable by annotators but rigorous enough to capture nuanced quality dimensions.
    • Decide which aspects are best handled by LLM-as-a-judge (LLMaJ) versus human review (Part 2).
    • Combine generic evaluators (e.g., coherence, harmlessness) wit domain-specific checks (e.g., insurance underwriting criteria).
  1. Validation & calibration
    Before scaling annotation, rubrics are stress-tested to:
    • Train expert annotators and evaluators, then calibrate them against gold standards.
    • Periodically validate LLMaJ outputs against human ratings to ensure alignment.
    • Refine rubric criteria and language to reduce ambiguity and improve inter-rater reliability (Part 3)—in some projects, alignment rates between LLMaJ and human reviewers increased by 30-50% after rubric refinement.
  1. Scale up and continuous feedback
    Once validated, rubrics move into production annotation pipelines to:
    • Deploy custom evaluators (LLM-based, code-based, or hybrid) to assist experts.
    • Use human reviews as calibration checks while LLMaJ handles bulk evaluation.
    • Feed continuous QA insights back into rubric refinement and LLMaJ prompt tuning.

Snorkel’s best practices

Over time, we’ve developed a set of best practices that anchor our rubric-driven process:

  • Metrics & KPIs that matter
    We focus on metrics that tie directly to data quality and the value it delivers:
    • Core metrics: Inter-rater reliability, rubric coverage, correlation of rubric scores with end-task outcomes.
    • ROI: Tracking these metrics quantifies quality improvements and operational impact.
    • Real-world examples: In domains like insurance underwriting, rubric-informed annotation improves both accuracy and efficiency.
    • LLMaJ alignment: Alignment rates between human reviewers and LLMaJ jumped from 37.3% to 93.95% when rubric access was provided (see Part 3).
Figure 2. Providing rubric context to LLMaJ improved human-model alignment from 37.3% to 93.95%, illustrating how structured evaluation enhances consistency.
  • Generic evaluators as force multipliers
    While prompt-specific rubrics are indispensable, a set of generic evaluators—like coherence, factual accuracy, and harmlessness—serve as cross-project baselines.
    • Purpose: Provide comparability across datasets.
    • Impact: Highlight systemic quality issues and maintain evaluation consistency across projects.
  • Iterative improvement through A/B testing
    Rubrics aren’t static; they evolve through experimentation.
    • Approach: Run controlled A/B tests to measure how new rubric criteria affect annotator consistency and model outcomes.
    • Example: More granular “factual consistency” scales improved inter-rater reliability without slowing annotation.
    • Scope: We also test instance-level rubrics—task-specific criteria for specialized domains (see Part 2).
    • Quality assurance: Validate through expert calibration, agreement measurement, and iterative refinement to ensure rubrics can guide automated evaluators like LLMaJ and downstream reward models.
Figure 3. Generic rubrics provide cross-project consistency, while instance-level rubrics enable fine-grained evaluation in specialized domains like insurance underwriting.
  • The ROI of rubric rigor
    Rubric-driven QA yields operational and business benefits:
    • Efficiency: Reduces rework, speeds annotator ramp-up, accelerates delivery.
    • Consistency: Builds a shared language of quality across teams.
    • Example: In insurance underwriting, Snorkel’s specialized benchmark—combining generic and domain-specific rubrics—surfaced edge cases, cut ramp-up time, and delivered measurable accuracy gains.

Snorkel’s quality checklist

At Snorkel, rubric-based evaluation follows a repeatable framework that ensures quality at scale. Here’s our checklist for building trustworthy AI data pipelines:

  1. Define “high quality” – Collaborate with stakeholders to translate objectives into measurable criteria.
  2. Design rubrics – Combine human insight with LLM-as-a-judge (LLMaJ) evaluators to capture nuanced quality signals.
  3. Validate and calibrate – Align rubric interpretations between experts and LLMaJ; refine until inter-rater reliability stabilizes.
  4. Scale with feedback – Deploy rubrics in production and continuously refine based on annotation and evaluator feedback.
  5. Measure impact – Track quality metrics such as inter-rater reliability, coverage, and correlation with task accuracy.
  6. Learn and iterate – Use A/B testing and rubric-driven insights to guide model and data improvements.

(Example: In insurance underwriting, this process surfaced high-risk edge cases and reduced ramp-up time while driving measurable accuracy gains.)

Bringing it all together

Rubric-based evaluation at Snorkel is not just a tool—it’s the backbone of how we scale trust in AI data pipelines. By combining rigorous design, collaborative validation, and continuous improvement, we’ve built a process that delivers on both quality and speed. This structured approach empowers our clients to move quickly without sacrificing confidence in their datasets—a critical enabler as AI applications grow in complexity and stakes.