name: data-science description: Data science and analytics expertise for statistical analysis, machine learning pipelines, data governance, business intelligence, predictive modeling, and analytics strategy. Use when building ML models, analyzing data, creating dashboards, or designing data architectures.

Data Science Expert

Comprehensive data science frameworks for analytics, machine learning, and data-driven decision making.

Data Strategy

Data Maturity Model

Level	Name	Characteristics
1	Ad Hoc	Manual, inconsistent, siloed
2	Opportunistic	Some automation, point solutions
3	Systematic	Defined processes, governance emerging
4	Differentiating	Data-driven decisions, advanced analytics
5	Transformative	AI-first, competitive advantage

Analytics Value Chain

DATA → INFORMATION → INSIGHT → ACTION → VALUE

PROGRESSION:
Descriptive: What happened?
Diagnostic: Why did it happen?
Predictive: What will happen?
Prescriptive: What should we do?
Autonomous: Self-optimizing systems

Statistical Analysis

Descriptive Statistics

CENTRAL TENDENCY:
- Mean: Sum / Count (sensitive to outliers)
- Median: Middle value (robust to outliers)
- Mode: Most frequent value

DISPERSION:
- Range: Max - Min
- Variance: Average squared deviation
- Standard Deviation: √Variance
- IQR: Q3 - Q1 (robust)

DISTRIBUTION SHAPE:
- Skewness: Asymmetry (0 = symmetric)
- Kurtosis: Tail heaviness (3 = normal)

For detailed inferential statistics and hypothesis testing, see Statistical Methods Reference.

Machine Learning

Algorithm Selection

Task	Algorithms	When to Use
Classification	Logistic Regression, Random Forest, XGBoost, Neural Networks	Categorical outcomes
Regression	Linear Regression, Ridge/Lasso, Random Forest, XGBoost	Continuous outcomes
Clustering	K-Means, Hierarchical, DBSCAN	Group discovery
Dimensionality Reduction	PCA, t-SNE, UMAP	Feature reduction, visualization
Anomaly Detection	Isolation Forest, One-Class SVM, Autoencoders	Outlier detection
Time Series	ARIMA, Prophet, LSTM	Sequential data
Recommendation	Collaborative Filtering, Content-Based, Matrix Factorization	Personalization
NLP	Transformers, BERT, GPT	Text understanding/generation

For detailed ML pipelines, feature engineering, and model monitoring, see ML Pipelines Reference.

Data Governance

Data Governance Framework

GOVERNANCE PILLARS:

POLICIES:
- Data ownership
- Data classification
- Data retention
- Data access
- Data quality standards

ROLES:
- Data Owner: Accountable for data domain
- Data Steward: Day-to-day quality management
- Data Custodian: Technical implementation
- Data Consumer: End user

PROCESSES:
- Data cataloging
- Metadata management
- Data lineage
- Issue resolution
- Change management

METRICS:
- Data quality scores
- Policy compliance
- Data access requests
- Issue resolution time

Data Quality Dimensions

Dimension	Definition	Measurement
Accuracy	Correct representation of reality	% records matching source
Completeness	All required data present	% non-null values
Consistency	Same across systems	% matching across sources
Timeliness	Available when needed	Latency, freshness
Validity	Conforms to format/rules	% passing validation
Uniqueness	No unwanted duplicates	Duplicate rate

Business Intelligence

BI Architecture

ARCHITECTURE LAYERS:

DATA SOURCES:
- Operational systems
- External data
- IoT/streaming

DATA INTEGRATION:
- ETL/ELT pipelines
- Data lakes
- Data warehouses

SEMANTIC LAYER:
- Business definitions
- Calculated metrics
- Hierarchies
- Relationships

PRESENTATION:
- Dashboards
- Reports
- Ad-hoc analysis
- Embedded analytics

Dashboard Design Principles

DESIGN PRINCIPLES:

PURPOSE:
- One clear objective per dashboard
- Know your audience
- Enable decisions

LAYOUT:
- Most important top-left
- Related items grouped
- Progressive disclosure
- Whitespace for clarity

VISUALS:
- Right chart for data type
- Consistent formatting
- Minimal decoration
- Color with purpose

INTERACTIVITY:
- Filters for exploration
- Drill-down capability
- Cross-filtering
- Tooltip details

Metric Design

METRIC DEFINITION TEMPLATE:

NAME: [Metric name]
DEFINITION: [Clear business definition]
FORMULA: [Precise calculation]
OWNER: [Responsible person]
DATA SOURCE: [Where it comes from]
GRAIN: [Level of detail]
FREQUENCY: [Update cadence]
DIMENSIONS: [Slicing attributes]
TARGETS: [Goals/benchmarks]
RELATED: [Related metrics]

Predictive Modeling

Use Case Framework

Use Case	Business Application	Approach
Churn Prediction	Retention programs	Classification
Demand Forecasting	Inventory planning	Time series
Lead Scoring	Sales prioritization	Classification
Price Optimization	Revenue management	Regression/RL
Fraud Detection	Risk mitigation	Anomaly detection
Recommendation	Personalization	Collaborative filtering
Customer Segmentation	Marketing targeting	Clustering
Lifetime Value	Customer investment	Regression

Data Ethics & Privacy

Ethical AI Framework

PRINCIPLES:

FAIRNESS:
- No discriminatory outcomes
- Bias testing across groups
- Regular auditing

ACCOUNTABILITY:
- Clear ownership
- Decision audit trails
- Escalation process

TRANSPARENCY:
- Explainable decisions
- Clear documentation
- User communication

PRIVACY:
- Data minimization
- Consent management
- Security controls

Bias Detection

BIAS TYPES:

HISTORICAL: Reflects past discrimination
REPRESENTATION: Training data not representative
MEASUREMENT: Proxy variables correlate with protected attributes
AGGREGATION: Single model for diverse populations
EVALUATION: Inappropriate benchmarks

FAIRNESS METRICS:
- Demographic Parity: Equal positive rates
- Equalized Odds: Equal TPR and FPR
- Individual Fairness: Similar inputs, similar outputs
- Calibration: Equal accuracy across groups

Analytics Team Structure

Team Roles

Role	Focus	Skills
Data Engineer	Pipelines, infrastructure	SQL, Python, Spark, Cloud
Data Analyst	Reporting, ad-hoc analysis	SQL, BI tools, Statistics
Data Scientist	Modeling, ML	Python/R, ML, Statistics
ML Engineer	Model deployment	MLOps, Software Engineering
Analytics Engineer	Data modeling	dbt, SQL, Data Modeling

Operating Models

Model	Description	Best For
Centralized	Single analytics team	Consistency, efficiency
Decentralized	Embedded in business units	Business alignment
Hub & Spoke	Central CoE + embedded	Balance of both
Federated	Shared platform, domain teams	Scale with autonomy

References

ML Pipelines Reference - Detailed ML pipeline, feature engineering, model development
Statistical Methods Reference - Inferential statistics, hypothesis testing, evaluation metrics

data-science

SKILL.md