The Data Science Lifecycle & CRISP-DM Process
The Data Science lifecycle is an iterative engineering process for extracting actionable business insights and training predictive models from raw data.
flowchart TD P1[1 · Problem Formulation] --> P2[2 · Data Collection & Sourcing] P2 --> P3[3 · Data Cleaning & Preprocessing] P3 --> P4[4 · Exploratory Data Analysis - EDA] P4 --> P5[5 · Feature Engineering] P5 --> P6[6 · Model Training & Hyperparameter Tuning] P6 --> P7[7 · Model Evaluation & Benchmarking] P7 --> EvalCheck{Meets Quality Threshold?} EvalCheck -- No --> P4 EvalCheck -- Yes --> P8[8 · Production Deployment & MLOps] P8 --> P9[9 · Observability & Stakeholder Reporting] P9 -.->|Continuous Feedback Loop| P1
The 9 Phases of the Process
Phase 1: Problem Formulation
- Define the business objective or hypothesis.
- Identify key stakeholders, success metrics (ROI, conversion, latency), and regulatory constraints.
- Determine project feasibility and scope.
Phase 2: Data Collection & Sourcing
- Ingest relevant datasets from databases, streaming event buses (Kafka), object stores (S3), and third-party APIs.
- Evaluate dataset licensing, provenance, and sampling bias.
Phase 3: Data Cleaning & Preprocessing
- Handle missing values (imputation vs deletion), deduplication, and outlier detection.
- Data normalization, scaling, and categorical encoding (One-Hot, Ordinal).
Phase 4: Exploratory Data Analysis (EDA)
- Analyze statistical distributions, variance, skewness, and inter-feature correlations using visualizations.
- Validate initial assumptions and identify potential confounding variables.
Phase 5: Feature Engineering
- Construct domain-specific features to maximize model signal-to-noise ratio.
- Feature selection and dimensionality reduction (PCA, t-SNE) to prevent the curse of dimensionality.
Phase 6: Model Development
- Select appropriate algorithmic families (tree-based XGBoost/LightGBM, neural networks, linear baselines).
- Automated hyperparameter optimization (Bayesian search, Optuna) using cross-validation folds.
Phase 7: Model Evaluation
- Evaluate on unseen holdout test sets using domain metrics: Precision/Recall, ROC-AUC, F1-score, MAE/RMSE.
- Bias, fairness, and error slice analysis.
Phase 8: Deployment & Maintenance (MLOps)
- Deploy artifacts via containerized microservices (Triton, KServe, vLLM).
- Continuous monitoring for covariate data drift and concept drift.
Phase 9: Communication & Insights
- Deliver executive dashboards and actionable business recommendations.