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data-warehouse-experimentation

Running experiments out of the data warehouse instead of via dedicated experiment platforms. SQL-based assignment, exposure logging discipline, metric definitions in dbt models, statistical analysis in SQL or Python, variance reduction with CUPED, sequential testing, and the operational tradeoffs vs platforms like Statsig and Optimizely. Triggers on warehouse-native experimentation, run experiments in BigQuery, run experiments in Snowflake, dbt experiments, SQL t-test, CUPED variance reduction, exposure log, sample ratio mismatch, sequential testing, mSPRT, doubly robust estimation, build vs buy experimentation. Also triggers when the team is choosing between platform and warehouse, building warehouse-native experiment infrastructure, auditing one, or running an experiment with a custom metric the platform cannot handle.

63

Quality

75%

Does it follow best practices?

Impact

No eval scenarios have been run

SecuritybySnyk

Passed

No known issues

Optimize this skill with Tessl

npx tessl skill review --optimize ./skills/data-warehouse-experimentation/SKILL.md
SKILL.md
Quality
Evals
Security

Quality

Content

50%

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

The skill is highly actionable with excellent executable code examples covering the full experimentation workflow, but it is far too verbose — it reads like a blog post or textbook chapter rather than a concise skill file. It explains concepts Claude already knows extensively, repeats key points across multiple sections, and inlines detailed content that belongs in the referenced files. The workflow could benefit from explicit validation checkpoints integrated into a step-by-step process rather than scattered across prose sections.

Suggestions

Cut the content by 50-60%: remove the editorial prose (closing section, lengthy platform-vs-warehouse justifications), explanations of well-known concepts (what CUPED stands for, what a t-test is, what dbt provides), and move detailed code examples into the reference files, keeping only minimal illustrative snippets in the main body.

Integrate the SRM check and other validation steps into an explicit numbered workflow with feedback loops (e.g., '5. Run SRM check SQL. If ratio deviates >1% from expected, STOP — debug assignment before proceeding to metric analysis').

Move the 11 pitfalls list, the full CUPED implementation, and the full Python/SQL analysis templates into their respective reference files, and keep only 1-2 sentence summaries with links in the main skill.

Provide the actual bundle reference files so the progressive disclosure structure is functional rather than aspirational.

DimensionReasoningScore

Conciseness

The skill is extremely verbose at ~400+ lines. It explains concepts Claude already knows (what platforms are, what CUPED stands for, what a t-test is, what dbt does), includes lengthy prose justifications for warehouse-native vs platform decisions, and repeats the same points multiple times (e.g., exposure logging discipline is covered in at least three separate sections). The 'closing' section is editorial opinion that adds no actionable value.

1 / 3

Actionability

The skill provides fully executable SQL and Python code for assignment hashing, t-tests, CUPED implementation, power analysis, and metric definitions in dbt. Code examples are copy-paste ready with realistic field names and patterns. The exposure log schema table is concrete and specific.

3 / 3

Workflow Clarity

The 12-consideration framework provides a clear checklist, and the architecture section establishes a data flow sequence. However, there are no explicit validation checkpoints or feedback loops in the workflow — for example, the SRM check is mentioned as important but not integrated into a step-by-step process with 'if SRM fails, do X' recovery steps. For a process involving destructive/batch operations on experiment data, this gaps caps the score.

2 / 3

Progressive Disclosure

The skill references 8 separate reference files with clear descriptions and links, which is good structure. However, the main SKILL.md itself contains enormous amounts of detail that should be in those reference files (full CUPED implementation, full t-test SQL, full Python analysis code, lengthy pitfalls list, extensive platform-vs-warehouse prose). The body should be a concise overview pointing to references, but instead it duplicates much of what the references presumably contain. Additionally, no bundle files were provided, so the references may not exist.

2 / 3

Total

8

/

12

Passed

Description

100%

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

This is an excellent skill description that thoroughly covers the domain of warehouse-native experimentation with highly specific capabilities, abundant natural trigger terms, and clear guidance on when to use it. It successfully distinguishes itself from both general data/SQL skills and platform-based experimentation skills. The description is comprehensive without being padded with fluff, and uses appropriate third-person voice throughout.

DimensionReasoningScore

Specificity

Lists multiple specific concrete actions and techniques: SQL-based assignment, exposure logging, metric definitions in dbt models, statistical analysis, CUPED variance reduction, sequential testing, and operational tradeoffs vs named platforms (Statsig, Optimizely).

3 / 3

Completeness

Clearly answers both 'what' (SQL-based assignment, exposure logging, metric definitions, statistical analysis, variance reduction, sequential testing, platform tradeoffs) and 'when' with explicit triggers ('Triggers on warehouse-native experimentation...', 'Also triggers when the team is choosing between platform and warehouse, building warehouse-native experiment infrastructure, auditing one, or running an experiment with a custom metric the platform cannot handle').

3 / 3

Trigger Term Quality

Excellent coverage of natural terms users would say: 'warehouse-native experimentation', 'run experiments in BigQuery', 'run experiments in Snowflake', 'dbt experiments', 'SQL t-test', 'CUPED', 'exposure log', 'sample ratio mismatch', 'sequential testing', 'mSPRT', 'build vs buy experimentation'. These are highly specific and natural terms a practitioner would use.

3 / 3

Distinctiveness Conflict Risk

Occupies a very clear niche: warehouse-native experimentation as opposed to platform-based experimentation. The specific mention of BigQuery, Snowflake, dbt, and named platforms like Statsig and Optimizely makes it highly distinguishable from general SQL, analytics, or A/B testing skills.

3 / 3

Total

12

/

12

Passed

Validation

90%

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation10 / 11 Passed

Validation for skill structure

CriteriaDescriptionResult

frontmatter_unknown_keys

Unknown frontmatter key(s) found; consider removing or moving to metadata

Warning

Total

10

/

11

Passed

Repository
rampstackco/claude-skills
Reviewed

Table of Contents

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