Data Science Portfolio

ML Validation & Data Quality

Machine learning validation, data quality, and AI/LLM evaluation connected to real product and quality-engineering problems.

M.S. in Data Science, AI, and Machine Learning, Boston University

Open to OpportunitiesPrimary focus: Applied AI · AI Evaluation · AI Platform. ML validation, data quality, and software quality engineering remain core strengths.EmailLinkedInGitHubResume PDF
Learning Path

Learning Path: From ML Concepts to Production AI Quality

I use this page to connect interview preparation with applied data science, model validation, and real product-quality problems.

Beginner

Foundations

  • Regression
  • Classification
  • Bias vs variance
  • Overfitting
  • Train/test split

Why it matters: These concepts define whether a model is learning real signal or just memorizing noise.

Intermediate

Intermediate ML

  • Random Forest
  • Gradient Boosting
  • Feature engineering
  • Model comparison
  • Error metrics

Why it matters: Model choice only matters when evaluation is honest, comparable, and tied to risk.

Applied

Model Validation

  • Baselines
  • Residual analysis
  • RMSE vs MAE
  • Fairness risk
  • Production readiness

Why it matters: Validation shows where a model fails, who is affected, and whether it is safe enough to use.

Advanced

Production ML / MLOps

  • Data drift
  • Monitoring
  • Golden datasets
  • Rollback criteria
  • Model cards

Why it matters: Production systems need monitoring, documentation, and rollback paths after the notebook ends.

Advanced

LLMs and Embeddings

  • Embeddings
  • Similarity search
  • Text classification
  • Metadata normalization
  • Retrieval quality

Why it matters: Semantic systems can improve discovery, but similarity is not the same as verified truth.

Interview Prep

Concept → Example → Interview Question

Each topic pairs interview questions with a portfolio example and the quality failure mode I would test before trusting the system.

Regression

Regression Interview Questions

  • What is the difference between RMSE and MAE?
  • Why can R² be misleading?
  • When would you choose Linear Regression over Random Forest?
  • What would you check before using a regression model in production?

WPH / Portfolio Example

Regression could support translation-demand forecasting or expected time-to-English-publication, but only after the World Publishing Houses dataset has enough historical examples across countries, languages, genres, and publisher types.

Quality Angle

A regression model should not be trusted just because it produces a number. I would check baseline comparison, residual patterns, outliers, data drift, and whether errors are larger for specific countries or categories.

Classification

Classification Interview Questions

  • What is the difference between precision and recall?
  • Why is accuracy dangerous with imbalanced classes?
  • When would you use a confusion matrix?
  • How do you choose a classification threshold?

WPH / Portfolio Example

World Publishing Houses could classify books into reader buckets such as “Read now in English,” “Coming soon,” or “Not yet in English.” Because the current dataset is still small for supervised ML and reader buckets may be imbalanced, accuracy alone would be misleading.

Quality Angle

Before training a classifier, I would check class balance, minority-class count, label definitions, and whether the model simply learns the majority class.

Feature Engineering

Feature Engineering Interview Questions

  • What makes a feature useful?
  • What is data leakage?
  • How do you handle categorical variables?
  • When should you drop a feature?

WPH / Portfolio Example

Possible World Publishing Houses features include original language, country, publisher activity, award status, translator presence, publication lag, verification status, and translation path.

Quality Angle

A feature can exist in the schema but still be useless for ML if it has no variation. For example, if almost every translation path is “Direct,” the model cannot learn pivot-translation behavior from that column.

MLOps

MLOps Interview Questions

  • What is data drift?
  • What should be monitored after model release?
  • What belongs in a model card?
  • How would you decide whether to roll back a model?

WPH / Portfolio Example

A World Publishing Houses recommendation or rights-signal model would need monitoring because publishing activity changes over time: awards, rights deals, new translations, publisher acquisitions, and seasonal release patterns can all shift the data.

Quality Angle

Production ML requires monitoring beyond uptime. I would track feature drift, prediction distribution, source freshness, error patterns, and confidence changes.

LLMs and Embeddings

LLMs and Embeddings Interview Questions

  • What is an embedding?
  • How is semantic search different from keyword search?
  • When can embeddings fail?
  • How would you evaluate retrieval quality?

WPH / Portfolio Example

Embeddings could help World Publishing Houses find similar books, cluster publishers, normalize messy metadata, or match translation records from different sources.

Quality Angle

Embedding similarity is not truth. I would test false matches, false misses, multilingual behavior, publisher-name ambiguity, and whether retrieval results are explainable to users.

ML Model Validation Case Study: Residential Property Values

Outcome: Compared Linear Regression, Random Forest, and Gradient Boosting models for residential property value prediction. Random Forest performed best among the tested models with RMSE of approximately $290,919, MAE of approximately $184,569, and R² of approximately 0.517. The project is framed as a model validation case study, showing how I evaluate performance, limitations, fairness risk, and production readiness.

The strongest insight was not that the model was production-ready, but that validation exposed clear limits: high prediction error, need for baseline comparison, possible location-proxy risk, and the importance of residual analysis before deployment.

Validation resultRandom Forest — RMSE ~$290,919 · MAE ~$184,569 · R² ~0.517.

What the Model Results Actually Mean

The Random Forest model performed best among the tested models, but the result also shows why validation matters. An R² of approximately 0.517 means the model explains some meaningful signal, but it is not strong enough for high-stakes appraisal decisions without additional feature engineering, market-specific validation, fairness review, and monitoring.

ModelRMSEMAEValidation takeaway
Random Forest~$290,919~$184,569~0.517Best tested model, but still limited for production use.
Gradient Boosting~$294,663Not reported~0.504Similar performance, slightly weaker than Random Forest.
Linear Regression~$336,465Not reported~0.354Baseline interpretable model; weaker fit for non-linear housing patterns.

A future improvement is to add a naive mean-prediction baseline so the model lift can be quantified against a simple non-ML benchmark.

Model Quality Review: What I Would Test Before Production

  • Data quality: I would verify missing values, duplicate records, outliers, stale property records, and inconsistent square-footage fields. Housing data can look numeric and clean while still containing unrealistic values that distort model behavior.
  • Residual analysis: I would compare prediction errors by region, price band, property type, and property age. A global RMSE can hide the fact that the model performs well on average homes but poorly on luxury homes, rural properties, or older housing stock.
  • Fairness and proxy risk: Location variables such as latitude, longitude, region, and ZIP-like fields can act as proxies for socioeconomic patterns. Before any production use, I would check whether error rates are higher for specific neighborhoods or property groups.
  • Baseline comparison: I would require a naive mean-prediction baseline and a simple interpretable model before treating the Random Forest result as meaningful. If the more complex model does not clearly improve over simple baselines, it should not be promoted.
  • Monitoring: Housing markets change over time. I would monitor drift in feature distributions, prediction errors, and regional market behavior after release. A model trained on older market conditions may become unreliable when interest rates or demand patterns change.
  • Release readiness: Before release, I would require documented validation data, model limitations, fairness checks, monitoring thresholds, rollback criteria, and a clear statement that the model supports analysis only — not automated appraisal decisions.

Capstone framing

Primary metricRMSE, supported by MAE and R².
Business use caseValuation analysis practice for understanding model behavior, not automated appraisal decisions.
Ethics lensLocation features can proxy socioeconomic patterns; monitoring, fairness review, and retraining are important.
  • Python
  • pandas
  • scikit-learn
  • Random Forest
  • Gradient Boosting
  • Model evaluation
  • Data validation
Current project · Applied AI quality

World Publishing Houses — AI Evaluation & Data Product Engineering

My current independent project: a source-backed publishing intelligence platform where I apply AI-evaluation, data-quality, and software-quality practices to AI-assisted research and multilingual data workflows.

What I build

  • A source-backed platform spanning publishers, books, countries, languages, market coverage, and rights signals.
  • AI-assisted research, enrichment, and summarization workflows evaluated for citation accuracy, source grounding, factual consistency, completeness, duplicates, and unsupported claims.
  • Automated audits and regression checks for coverage, work identifiers, cover matching, search, discovery, multilingual content, and AI-agent workflows.

Why it matters

It is a working example of AI evaluation and quality engineering in practice: evaluating AI- and LLM-assisted outputs against sources, catching failure modes early, and keeping trust and provenance visible to users.

  • LLM evaluation
  • Source grounding
  • Factual consistency
  • Data quality
  • Provenance

Tools and concepts

Technologies and methods I use across applied AI, data science, model validation, and production quality engineering.

Python data stack

Pandas, NumPy, scikit-learn, notebooks, data cleaning, model comparison, and evaluation.

ML concepts

Regression, classification, clustering, embeddings, decision trees, gradient boosting, cross-validation, and error analysis.

Engineering context

SQL, API testing, logs, automation, CI/CD awareness, cloud/data pipeline concepts, and production quality thinking.