Exploratory Data Analysis (EDA)
EDA is a structured visual and statistical approach for initial investigation of datasets to identify patterns, outliers and assumptions.
Classification
- ComplexityMedium
- Impact areaBusiness
- Decision typeDesign
- Organizational maturityIntermediate
Technical context
Principles & goals
Use cases & scenarios
Compromises
- Overgeneralizing from random patterns.
- Incorrect imputation decisions can introduce bias.
- Incomplete documentation leads to lack of reproducibility.
- Involve domain experts early.
- Reproducibility: version notebooks and reports.
- Iterative refinement: work from coarse to detailed.
I/O & resources
- Raw data as CSV, Parquet or database export
- Schema documentation and field descriptions
- Access to visualization and analysis tools
- EDA report with visualizations and statistics
- Recommended cleaning and imputation rules
- Prioritized hypotheses for follow-up analyses
Description
Exploratory Data Analysis (EDA) is an iterative, methodical approach to examining datasets using visualization, summary statistics and simple transformations. The goal is to uncover patterns, outliers and hypotheses for further analysis. EDA reduces uncertainty and informs model selection, feature engineering and business questions.
✔Benefits
- Rapid identification of data issues and outliers.
- Improved feature selection and model robustness.
- Better alignment between data and business requirements.
✖Limitations
- Not automated: requires human interpretation.
- Scalability with very large raw data can be limited.
- Subjectivity: different analysts may reach different conclusions.
Trade-offs
Metrics
- Missing value rate
Percentage of missing entries per field as an indicator of data quality.
- Number of detected outliers
Number of unusual values according to defined method per dataset.
- Correlation between key variables
Measure to identify redundant or highly linked features.
Examples & implementations
EDA in customer churn analysis
Examining customer behavior, segments and churn patterns to identify relevant predictors.
EDA for payment fraud detection
Detecting unusual transaction patterns and anomalies as a basis for feature development.
Product metrics exploration
Analysis of usage metrics to prioritize improvements and identify measurement errors.
Implementation steps
Define data selection and sampling
Generate exploratory visualizations and statistics
Document issues and anomalies
Derive imputation and cleaning rules
Produce report and recommendations for stakeholders
⚠️ Technical debt & bottlenecks
Technical debt
- Insufficiently documented transformation rules.
- Missing standard pipelines for reproducibility.
- Legacy data formats hinder automated analyses.
Known bottlenecks
Misuse examples
- Drawing conclusions from small, non-representative samples only.
- Automatically removing outliers without cause analysis.
- Interpreting EDA results as definitive proof of causality.
Typical traps
- Mistaking correlation for causation.
- Ignoring time zone or timestamp inconsistencies.
- Over-reliance on automated profiling tools.
Required skills
Architectural drivers
Constraints
- • Privacy and compliance restrictions
- • Limited availability of data samples
- • Lack of standardized metrics