Commercial Data Science Case Study

Estimating marketing impact and budget trade-offs for fashion ecommerce.

A UK fashion retailer needs a credible way to connect marketing spend, incrementality evidence, uncertainty, and commercial planning. This lab turns that measurement problem into a working analyst dashboard and reusable Python package.

Business Setting UK fashion ecommerce

Paid, owned, organic, promotion, and ecommerce sources.

Core Methods MMM and incrementality

Econometrics, adstock, saturation, priors, calibration, and uncertainty.

Decision Output Budget planning

Profit-aware scenarios, constrained optimization, and executive summaries.

Business Context

The retailer wants to understand how paid and owned marketing channels contribute to revenue, new-customer growth, and profit. The team needs more than channel correlation: it needs a defensible workflow for estimating incremental contribution while accounting for seasonality, promotions, carryover, diminishing returns, and experiment evidence.

Measurement Question

How should a fashion ecommerce brand allocate weekly marketing budget across channels while accounting for data quality, uncertainty, experiment calibration, and practical business constraints?

Product Workflow

Validate Source Data

Check weekly marketing schema and upstream connector exports before modeling.

Assemble Weekly Dataset

Map ecommerce, GA4, paid media, CRM, affiliate, influencer, display, and control exports into an MMM-ready weekly table.

Diagnose Readiness

Review source coverage, history length, outcome quality, and channel availability.

Model Incremental Impact

Fit baseline econometrics, MMM-style response curves, Bayesian intervals, and experiment-informed calibration.

Plan Budget Scenarios

Compare gross-margin-aware budget options and constrained allocation recommendations.

Current Outputs

Analyst Dashboard

Revenue, orders, new customers, media spend, channel mix, promotions, and readiness checks.

Modeling Diagnostics

Holdout performance, contribution, ROI, response curves, uncertainty, and Bayesian summaries.

Evidence and Governance

Lift-test uploads, quality scoring, approved-only calibration, and experiment-informed priors.

Connector Workflow

Templates, validation, weekly assembly, source diagnostics, and downloadable assembled CSVs.

Commercial Planning

Profit-aware scenarios, channel constraints, allocation optimization, and planning caveats.

Stakeholder Summary

Automated executive summary language, model-run report, and JSON manifest for review.

Recommendation Governance

Readiness gates for model accuracy, evidence, profit impact, spend movement, and history length.

Technical Stack

Python Pandas Statsmodels Plotly Streamlit Pytest Ruff uv GitHub Actions

Data Notes

The included dataset is generated deterministically for portfolio use. It is not ASOS data and does not copy any private brand data. Uploaded files are parsed in memory in the current Streamlit version.