Hi everyone,
 

In this post, I’ll walk you through regex-based detection checks. Understanding regex-based detection checks is crucial for ensuring data quality, validation, and anomaly detection. One common question that arises is about the % threshold when specifying such a check.

What does % threshold mean in regex-based detection checks?

When applying a regular expression (regex) check, the % threshold represents the proportion of data entries that must match the regex pattern in order for the check to pass.

For example, if you set the threshold to 70%, it means that at least 70% of the data elements must match the regex pattern for the detection check to be considered successful.

Common misconception: Matching data vs. matching regex

A frequent point of confusion is whether the threshold means:

• 70% of the data should match the regex (Correct)
• 70% of the regex should match each data element (Incorrect)

A regex pattern either matches or doesn’t for each data element - it does not partially match individual elements by percentage. Instead, the check considers the proportion of elements that fully match.

Example: How % threshold works in regex validation

Let’s assume you are applying a regex pattern check to 100 data entries:

• If the threshold is 70%, at least 70 out of 100 entries must match the regex for the check to pass.
• If only 65 entries match, the check fails.
• If 85 entries match, the check passes.

Why is % threshold important for Data Quality?

Ensuring a sufficient proportion of data matches a given pattern is vital for data validation, anomaly detection, compliance and data quality assurance. Setting an appropriate threshold helps balance false positives and false negatives, making your data validation process more accurate and reliable.

By implementing regex-based detection checks, organizations can maintain clean, structured, and trustworthy datasets for analytics, reporting, and decision-making.

What are some challenges you’ve faced in regex-based detection checks? Let’s discuss in the comments below! 👇