GEEYOON (JIYUN) LIM

Data Analyst & Analytics Engineer

I turn complex operational, customer, and market data into reliable, decision-ready products. My work connects data quality, analytics engineering, experimentation, and applied AI evaluation.

Each case study shows how I approached the problem, what evidence I produced, and what business decision the work supports.

Selected work

Five projects. Five forms of evidence.

Each case study explains the problem, the system, the finding, and the decision. Tools support the story. They do not replace it.

01Analytics Engineering
Data Engineering

Enterprise Spend Analysis Pipeline

A controlled analytics and monitoring pipeline for spend, contract, vendor, and approval data.

PythonMySQLdbtAirflowPower BIGrafanaStreamlit
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02Product Analytics

E-Commerce Product Analytics

Conversion funnel, retention, and revenue-driver analysis.

PythonSQLFunnel analysis
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03Operational Reporting
Data Quality

NHS Workforce Capacity & Service Delivery Reporting

A repeatable monthly reporting process for operational managers.

PythonSQLExcelPower BI
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04AI Validation
Governance

AI-Augmented Customer Support Operations Analytics

Measured validation defines where automation must stop.

AI evaluationHuman reviewGovernance
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05Statistical Analytics

Macro-Financial Datasets

Regime analysis with explicit bias controls and stability tests.

PythonPostgreSQLSensitivity testing
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System thinking

From prototype to production.

A prototype shows that a system can work. Controls show that users can trust it when conditions change.

How I work

Controls before claims.

A useful result must be repeatable, tested, and connected to a user decision.

01

Build for repeatability

I prefer controlled pipelines to one-time analysis.

02

Validate before automation

I test data and model outputs before I automate decisions.

03

Design for the user

I select metrics and views from the decision that the user must make.

Concept library

Ideas linked to evidence.

Each concept has a short definition, a visual explanation, an implementation, and proof from a project.

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Pipeline reliability

Idempotency

A repeated run produces the same valid result.

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Transformation

dbt modelling

Governed models move business logic out of the dashboard.

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