Train-Test Data Leakage Detection

uniquenesscritical

Validates that no record IDs appear in both the training and test datasets. Data leakage between training and test sets leads to artificially inflated model performance metrics and unreliable AI systems. Under EU AI Act Article 10, datasets must support proper evaluation of AI system performance.

v1.0.0by dqhub435 downloads4.3 (37)

data-leakagemodel-evaluationuniquenessai-acttrain-test-splitdata-governance

Try This Rule

Parameters

column_namestringrequired

The column containing email addresses

thresholdfloatdefault: 0.99

Minimum fraction of valid emails (0.0 to 1.0)

Compliance Mapping

EU AI ActArticle 10 — Data and Data Governance

NIST AI RMFMEASURE 2.6

ISO/IEC 5259ISO/IEC 5259-1:2024 — Data Quality for AI

Install

soda

checks for {{table_name}}:
  - invalid_percent({{column_name}}) < {{(1 - threshold) * 100}}:
      valid regex: '^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$'

dbt

{% test valid_email(model, column_name) %}
select {{ column_name }}
from {{ model }}
where {{ column_name }} not regexp '^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,}$'
{% endtest %}

sql

SELECT COUNT(*) as total,
  SUM(CASE WHEN {{column_name}} REGEXP
    '^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,}$'
    THEN 1 ELSE 0 END) as valid
FROM {{table_name}}

Great Expectations

{
  "expectation_type": "expect_column_values_to_match_regex",
  "kwargs": {
    "column": "{{column_name}}",
    "regex": "^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,}$",
    "mostly": {{threshold}}
  }
}

spark

from pyspark.sql.functions import col
pattern = r'^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$'
invalid = df.filter(~col("{{column_name}}").rlike(pattern)).count()

Test Data

Passing Examples

id	value
1	alice@example.com
2	bob.smith@company.co.uk
3	charlie+tag@domain.org

Failing Examples

id	value
1	not-an-email
2	@missing-local.com
3	spaces in@email.com

CLI

Terminal

npx dqhub install train-test-leakage-detection --format soda --table YOUR_TABLE
npx dqhub install train-test-leakage-detection --format dbt --model YOUR_MODEL
npx dqhub install train-test-leakage-detection --format sql --dialect snowflake