Table 4 Example of data quality issues

Single data source

Cell instance level

Missing data

●

●

Incorrect data and references, Data entry errors and Misspelling

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Irrelevant data

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Outdated data

●

Misfielded and contradictory values

●

●

●

Dataset schema level

Domain and Uniqueness constrains, Functional dependency violation

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Wrong data type, poor schema design

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Referential integrity violation, lack of integrity constraints

●

●

●

Multiple data source

Cell instance level

Different units, representations, Structural conflicts

●

Different aggregation levels, Inconsistent aggregation

●

●

Temporal mismatch, inconsistent timing

●

Dataset schema level

Heterogeneous data models and schema design

●

●

●

Different encoding formats

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