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Your business in your hands.

Oscar Araya Díaz · Data Analyst · Python & SQL · Santiago, Chile 🇨🇱

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Focused on helping business to take control on their desicions. My motto is "Your business in your hands". I ask the right questions to uncover the most impactful insights. I build end-to-end data projects: from extracting and cleaning real-world data to analysis, visualization, and automation.

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Projects

How Can Menu Engineering, Peak-Hour Demand, and Cross-Selling Boost a Coffee Shop’s Profitability?

Coffee Shop Sales Analysis & Interactive Power BI Dashboard

PythonpandasMatplotlibSeabornPower BI

A comprehensive data analysis of sales performance and customer behavior focused on optimizing the business strategy and profitability of a coffee shop using Python and Power BI.

Data Pipeline Transformation Slicer

Select pipeline state to interactively inspect how chaotic raw ingestion filled with anomalies transforms into a pristine model.

Pipeline Status Raw Ingestion
Anomalies Detected 10 Critical Errors
Data Integrity 42.8%
🚨 [State: Raw Dataset] - Extreme corruption: NaN values, negative prices, duplicate IDs, typos and format breaks.
tx_id timestamp item price payment store_loc customer_id
TX1001 2026-01-01 08:30 Latte 3.50 Credit Downtown C-4091
TX1002 MISSING_DATE Espresso ERROR_NaN Debit Downtown C-8812
TX1003 01/01/2026 09:15 Croissant -99.99 Cash Airport C-1029
TX1004 2026.01.01 M#cha 4.00 Credit Downtown C-3304
TX1001 2026-01-01 10:20 Muffin FREE_PROMO Cash Airport C-5012
TX1006 2026-01-01 11:05 Cappuccino 3.75 ???_UNKNOWN Downtown C-9921
TX1007 2026-01-01 11:40 Tea 2.00 Credit ERROR_404 NULL_USER
TX1008 BAD_DATE_FORMAT Americano 2.80 Debit Downtown C-2290

Final Interactive Dashboard (Power BI)

Consolidated business intelligence view designed for executive decision-making and operational control.

Power BI Dashboard Demo GIF showing business performance and metrics
Download Power BI (.pbix) ↓

Chart-Backed Analysis

BCG Matrix (Portfolio)
BCG Matrix product portfolio analysis chart

Products categorized by profitability and sales volume.

Time-of-Day Demand
Time of Day Demand chart showing customer traffic patterns

Identification of bimodal operational peaks.

Service Channel
Service Channel consumption preference chart

In-store vs. takeaway consumption preference.

Payment Methods
Payment Methods adoption distribution chart

Digital payment adoption exceeding 85%.

Executive Summary

Margin % vs. Dollar Profit Mismatch

79.8% Revenue (Coffee + Sandwiches)

• Teas (High Margin Illusion): High percentage margin (70%-77%), but return very low cash ($1,365 - $1,483 per unit, BCG Dog quadrant).

• Sandwiches (Profit Engine): Lowest percentage margin (62.4%), but yield the highest dollar profit per unit (e.g., Pulled Beef Croissant yields +$2,882 net profit/unit).

• Business Concentration: Coffee ($21.4M) and Sandwiches ($19.0M) drive nearly 80% of total revenue ($50.4M).

How Does the Chilean State Spend, and Where Are the Real Opportunities for New Suppliers?

Exploratory Data Analysis (EDA) & Mercado Público Dashboard in Python & Power BI

PythonpandasNumPyMatplotlibSeabornPower BI

Exploratory Data Analysis (EDA) of ~1.1 million public purchase orders from Mercado Público (ChileCompra) to identify spending patterns, geographic concentration, and accessible market niches for suppliers.

Final Interactive Dashboard (Power BI)

Interactive assessment of state resource allocation and regional/sectoral distribution.

Interactive demo of Mercado Público Power BI Dashboard
Download Power BI (.pbix) ↓

Data Cleaning & Key Decisions

  • Line vs. Order Granularity: Analyzed item line net totals (total_linea_neto) instead of total order amounts to prevent double counting
  • Currency & VAT Reconciliation: Verified 99.4% CLP transactions and reconciled gaps between net and gross order values.
  • Geographic Entity Normalization: Consolidated 32 inconsistent regional labels into the 16 official Chilean regions via Unicode normalization and keyword string matching.
  • Pedagogical Principle: Deep diagnosis of raw data anomalies prior to applying automated transformations.

Chart-Backed Analysis & Pareto Breakdown

Pareto Chart by Agency
Pareto Chart Agency concentration analysis

Top 10 entities absorb 84.1% of the total budget.

Sector Breakdown
Sector Breakdown public spending

IT & Telecom leading macro sector spending at 42.8%.

Category Breakdown
Category Breakdown spending distribution

Granular distribution showing passenger transport & logistics dominance.

Market Opportunity Matrix

Distinguishing real open niches from captive markets based on supplier count and liquidity.

Category / Sector Market Type Suppliers Spend / Supplier Diagnosis
Transportation & Courier Open / Dynamic 94 $140.09T CLP 🟢 Niche #1: High transaction flow.
IT & Telecom (Sub 1782) Open / Dynamic 364 $26.33T CLP 🟢 Niche #2: Highest transactional turnover.
IT & Telecom (Sub 1802) Moderate 429 $28.69T CLP 🟢 Niche #3: High accumulated liquidity.
Financial Services Closed / Concentrated 6 $630.98T CLP 🔴 False Niche: Institutional banking oligopoly.
Mining Machinery Closed / Concentrated 8 $37.12T CLP 🔴 False Niche: Extreme technical exclusivity.
Executive Summary

Public Procurement EDA

💡 Insight EDA Analysis

• Bidding Concentration: A significant portion of procurement transactions focuses on smaller public tenders, identifying key operational bottlenecks in award decisions.

• Optimization Opportunity: Strategic adjustments in procurement filtering reveal outlier bidding patterns and drive clearer decision-making for budget planning.

How Much Value Does Your Money Lose to Inflation, and How Does the UF Protect It?

Inflation ETL Pipeline & Dashboard in Chile (2015–2025)

PythonrequestspandasPostgreSQLSQLAlchemyPower BIWindows Task Scheduler

An end-to-end automated data pipeline that extracts CPI and UF series from the Central Bank of Chile (BCCh) REST API, cleans and transforms the data, loads it idempotently into PostgreSQL, and visualizes purchasing power loss and inflation protection in Power BI.

ETL Pipeline Execution Cycle

Automated continuous execution flow (click or hover to inspect a stage):

Loading pipeline...

Final Interactive Dashboard (Power BI)

Visualizing 11 years of macroeconomic data (2015–2025): Chilean Peso purchasing power erosion vs. UF inflation hedging.

BCCh Inflation Pipeline Power BI Dashboard Demo
Download Power BI (.pbix) ↓

Pipeline Architecture & Specifications

Component Technical Selection Technical Justification
Extraction BCCh REST API (requests) Direct HTTP requests for full response control over third-party SDK wrappers.
Transformation Python (pandas) Daily to monthly resampling, base-100 index alignment, and YoY inflation calculations.
Persistence PostgreSQL + SQLAlchemy Idempotent upsert loads (ON CONFLICT DO UPDATE) to eliminate duplicate rows on rerun.
Orchestration Centralized main.py + Windows Scheduler Automated monthly execution with exponential backoff retries and execution logging.
Key Engineering Decisions:
  • Idempotent Database Upsert: Re-running the pipeline will update existing records rather than creating duplicate entries.
  • Script-Anchored Absolute Paths: Uses Python pathlib to guarantee consistent execution whether triggered by CLI or Task Scheduler.
  • Layered Error Contextualization: Separate logging and retry mechanisms between extraction and orchestration.

Key Empirical Findings (2015 – 2025)

Quantitative evaluation of currency depreciation and real-value preservation mechanisms in Chile.

💡 Key Finding: Between 2015 and 2025, the Chilean Peso lost nearly 38% of its purchasing power (CPI grew from 100 to ~160). Concurrently, the UF index matched this growth (~162), empirically proving that UF perfectly shields capital against inflation over long horizons.
View code on GitHub →

Contact

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