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duncanalyst/README.md

Hi, I'm Duncan Chicho 👋

Data Analyst | Excel • SQL • Power BI • Python

🎓 Actuarial Science Background | Statistical Rigour Meets Business Impact

🌍 Open to Remote Opportunities | 🕐 GMT+3

Typing SVG

🎯 About Me

I am a data analyst with an Actuarial Science foundation, combining mathematical precision with business storytelling. I specialise in transforming complex datasets into clear, actionable insights that drive strategic decisions.

Over the past months I have built a structured portfolio across Excel, SQL and Power BI — working on real datasets in banking, healthcare, retail and HR analytics. Every project is published on GitHub with full documentation and board-ready findings.

What sets me apart:

  • 🧠 Actuarial background — advanced statistical thinking built in, not bolted on
  • 📊 Business-first approach — I answer the question behind the question
  • 🔁 End-to-end capability — from raw data to executive recommendation
  • 🌍 International ambition — building skills and portfolio to work globally

🛠️ Technical Skills

Spreadsheets Database Visualisation Programming
Excel SQL Power BI Python
Power Query • DAX • VBA T-SQL • CTEs • Window Functions Dashboards • DAX Measures • Drill Through pandas • matplotlib

Excel: Power Query, Power Pivot, DAX, VBA Macros, Dynamic Arrays, XLOOKUP, Statistical Analysis, Scenario Manager, Goal Seek, Dashboard Design

SQL: T-SQL, SELECT/WHERE/GROUP BY/HAVING, Aggregate Functions, INNER & LEFT JOINs, Subqueries, CTEs (multi-level), Window Functions (RANK, PARTITION BY, LAG, LEAD, Running Totals), CASE WHEN, Date Functions, String Functions, Primary & Foreign Keys, Views, Stored Procedures, Indexes, Data Quality Auditing

Power BI: SQL Server Connector, Import Mode, Power Query (M Language), Star Schema Modelling, DAX Measures, Calculated Columns, Drill Through, Bookmarks, Page Navigation, KPI Cards, Multi-page Dashboard Design


🚀 Portfolio Projects

Interactive 3-page Power BI dashboard built on the Olist SQL analysis — full end-to-end pipeline

Metric Finding
Total Orders 99,441 across 4 relational tables
Total Revenue $16.01M across 27 Brazilian states
Top State SP — $5.77M revenue | 8.7 day avg delivery
Credit Card Share 78.34% of total revenue
Repeat Customer Rate 0.00% — not a single repeat buyer
Avg Delivery 12 days Brazil average | 97.02% delivered

Key Features: Drill through from state chart to delivery detail page • Bookmarks reset button • Year slicer • Hidden drill through page • DAX measures validated against SQL queries

Power BI DAX Power Query SQL Server Connector Star Schema Drill Through Bookmarks M Language

🔗 Built on: Olist E-Commerce — SQL Analysis


Detecting 473 fraud cases among 283,726 real credit card transactions

Metric Finding
Fraud Rate 0.1667% — 473 cases in 283,726 transactions
Fraud Avg Amount $123.87 vs Legitimate $88.41 — 40% higher
Peak Fraud Hour 2am — 1.4550% rate, nearly 10x average
Fraud in Normal Transactions 93.9% — Z-Score alone misses 444 of 473 cases
Total Fraud Value $58,591.39 across 473 transactions

Key Recommendation: Multi-factor detection combining amount, time and behavioural signals — Z-Score alone is insufficient.

T-SQL Views Stored Procedures Indexes Z-Score Anomaly Detection ROW_NUMBER() PERCENTILE_CONT Data Cleaning Deduplication


Identifying the key drivers of employee attrition across 1,470 IBM records

Metric Finding
Overall Attrition Rate 16.12% — 237 employees left
Highest Risk Department Sales — 20.63% attrition rate
Income Gap Leavers earned $2,045/month less than stayers
Highest Risk Age Group Under 25 — 39.18% attrition rate
Highest Risk Role Sales Representatives — 39.76% attrition | $2,626 avg income
Most Stable Role Research Directors — 2.50% attrition | $16,033 avg income

Key Recommendation: Compensation is the strongest predictor of retention across all 9 job roles. Revising Sales Representative pay is the single highest-return intervention available.

T-SQL CTEs Window Functions RANK() PARTITION BY Subqueries CASE WHEN GROUP BY CAST


Multi-table revenue, delivery and retention analysis across 99,441 orders

Metric Finding
Order Growth 1 order (Sep 2016) → 7,289/month (Nov 2017) in 14 months
Credit Card Revenue Share 78.34% — $163 avg order value
Delivery Performance Only 31.82% arrive within 1 week — 12 day average
Top State SP — $5.77M revenue, 8 day avg delivery
Repeat Customers 0% — every customer purchased exactly once

Key Recommendation: Zero repeat buyers is an existential retention risk — every customer acquired is lost after one purchase.

T-SQL Multi-table JOINs CTEs Window Functions Date Functions Primary Keys Foreign Keys Data Quality Auditing UNION ALL

🔗 Also available as: Power BI Dashboard — Interactive 3-page dashboard completing the full Data → SQL → Power BI pipeline


Multi-dimensional revenue analysis across time, geography and product categories

Metric Finding
Top Region West — 31.4% of total revenue
Top State California — 19.7% concentration risk
H1 2019 Forecast $340,533 (FORECAST.ETS)
Growth Required for $1M Target 77%

Key Recommendation: California concentration represents portfolio risk — diversification into underperforming regions would reduce revenue volatility.

Power Query Power Pivot DAX VBA Macros FORECAST.ETS Scenario Manager Goal Seek Dynamic Arrays


Loan default risk analysis across a KES 12.28M banking portfolio

Metric Finding
Portfolio Value KES 12,285,000
Overall Default Rate 20%
Highest Default Region Nairobi — 60% of all defaults

Key Recommendation: Nairobi concentration in both portfolio value and defaults signals a geographic risk — regional diversification and tighter Nairobi credit scoring criteria warranted.

Power Query XLOOKUP Pivot Tables Conditional Formatting KPI Dashboard


Patient admission, cost and risk analysis across 40,235 records

Advanced Excel Statistical Analysis Dashboard Design Data Cleaning


🎓 Education & Background

Actuarial Science — University education in statistical modelling, risk assessment and financial mathematics. This foundation gives my data analysis a level of mathematical rigour that goes beyond standard analyst training.

Self-directed Upskilling:

  • ✅ Excel — Power Query, DAX, VBA, Statistical Analysis
  • ✅ SQL — T-SQL, Window Functions, CTEs, Advanced Queries
  • ✅ Power BI — Dashboards, DAX Measures, Drill Through, Bookmarks, SQL Server Connector
  • 📅 Python — pandas, matplotlib, scikit-learn (Planned)

🎯 Currently Seeking

Junior to Mid-level Data Analyst roles — remote — where I can:

  • ✅ Deliver business-ready analysis and dashboards
  • ✅ Apply statistical expertise to real business problems
  • ✅ Work with cross-functional teams in fast-paced environments
  • ✅ Grow toward senior analyst and data science capability

Industries of interest: Financial Services, Banking, Consulting, Healthcare, Telecoms


📫 Let's Connect

LinkedIn Email GitHub


💡 The thinking doesn't change. Only the syntax does.

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  1. healthcare-analytics-dashboard healthcare-analytics-dashboard Public

    Excel-based healthcare analytics project — Power Query, Power Pivot, DAX, Array Formulas & VBA. 40,235 patient records. Executive dashboard with 5 business insights.

    1

  2. global-superstore-sales-dashboard global-superstore-sales-dashboard Public

    Excel-based retail sales performance, forecasting & scenario analysis dashboard using Power Query, Dynamic Arrays, FORECAST.ETS and What-If Analysis

  3. olist-ecommerce-sql-analysis olist-ecommerce-sql-analysis Public

    SQL analysis of 99,441 Olist e-commerce orders across 4 relational tables — revenue trends, delivery performance and customer retention insights using multi-table JOINs, CTEs and Window Functions

    TSQL

  4. credit-card-fraud-detection-sql credit-card-fraud-detection-sql Public

    Advanced SQL analysis of 283,726 credit card transactions — fraud pattern detection using Views, Stored Procedures, Indexes and Z-Score anomaly detection on Microsoft SQL Server

    TSQL

  5. Olist-ecommerce-powerbi Olist-ecommerce-powerbi Public

    Power BI dashboard — 99,441 Olist orders visualised across 2 pages | Revenue, delivery performance and 0% customer retention finding | Built on SQL Server foundation