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Data quality

As explained in Delivering Machine Learning Projects: From design to deployment

Data quality is the degree to which data is accurate, complete, consistent, relevant, timely, and fit for its intended use.

Data quality is the degree to which data is accurate, complete, consistent, relevant, timely, and fit for its intended use. In an ML project, survey the data early to locate issues that may require investigation, resolution, or avoidance. section 5.2.4

Turn the quality survey into concrete checks:

  • Inspect representative records for useful information, ambiguity, and patterns that may support the intended application. section 5.2.4
  • Count empty records, NULL values, and placeholder values such as “.” or “n/a” that conceal missing mandatory fields. section 5.2.4
  • Assess whether apparent regularities are useful, expected, irrelevant, or signals of unusable data. section 5.2.4

Smart-building incident records

Review incident descriptions and resolutions for actionable content. Reports about HVAC failures may relate naturally to unusual sensor readings, but extracting structured facts such as affected floors can be difficult. Inspect more than a handful of records before deciding whether the data is suitable. section 5.2.4

select count(*) from incidents;
>1781

select * from incidents limit 1;
>23-05-2021, CRITICAL, 360, "HVAC failure…", "affinity engineer..")

Use the incident count and sample-record query as a compact starting point for a data-quality survey. section 5.2.4

How Delivering Machine Learning Projects: From design to deployment covers it

How deep it goes
Inspects records, missingness, placeholders, and visible patterns, while deferring deeper investigation to exploratory data analysis.
Examples
Uses smart-building incident text, SQL record samples, missing-value checks, and image collections containing potentially irrelevant content.
What you can do after
Evaluate whether data contains actionable information and decide what to investigate, resolve, or avoid.
How it connects
Connects data quality with unstructured data, exploratory data analysis, sensor readings, and machine learning projects.

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This explainer was generated by Manning's knowledge graph from the text of Delivering Machine Learning Projects: From design to deployment. The section links point to the parts of the book it draws on.