Data analytics engineer and BI leader with experience turning raw data into decisions. Portfolio of dashboards, data pipelines, and analytical projects. Based in St. Augustine, FL.https://rotunno.io/https://rotunno.io/blog/iran-war-oil-macro-analysis/https://rotunno.io/blog/iran-war-oil-macro-analysis/Instead of assuming oil explains everything, I used FRED data to test where it's actually statistically significant — across inflation, unemployment, payrolls, industrial production, and GDP. The results were more nuanced than the headlines suggest.Fri, 20 Mar 2026 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/gas-prices-32-percent-surge/https://rotunno.io/blog/gas-prices-32-percent-surge/National average gas prices hit $3.84/gallon — a 32% jump in one month. I ran a normalized comparison of Brent crude against major oil producers to understand what the market is actually pricing in.Thu, 19 Mar 2026 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/crisp-dm-framework/https://rotunno.io/blog/crisp-dm-framework/CRISP-DM is the closest thing data analytics has to a universal playbook. Here's what the six phases actually mean in practice — and why I keep coming back to it.Tue, 11 Mar 2025 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/intro-to-scikit-learn/https://rotunno.io/blog/intro-to-scikit-learn/Scikit-Learn is the workhorse of applied machine learning in Python. Here's what it does, why it's worth learning deeply, and a practical example to get you started.Tue, 11 Mar 2025 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/entropy-vs-gini/https://rotunno.io/blog/entropy-vs-gini/Both entropy and Gini impurity measure how mixed a node is in a decision tree — but they differ in computation, behavior, and when each makes sense to use.Sat, 08 Feb 2025 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/lasso-vs-ridge-regression/https://rotunno.io/blog/lasso-vs-ridge-regression/Both Lasso and Ridge add a penalty to linear models to prevent overfitting — but they behave very differently. Here's when to use each and how to implement both.Sat, 08 Feb 2025 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/titanic-ml-from-disaster/https://rotunno.io/blog/titanic-ml-from-disaster/The Titanic dataset is the classic ML classification benchmark. Here's a full walkthrough — feature engineering, Random Forest, Logistic Regression, and what the results actually mean.Sat, 08 Feb 2025 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/grid-search-hyperparameter-tuning/https://rotunno.io/blog/grid-search-hyperparameter-tuning/Grid Search exhaustively evaluates every combination in a parameter grid using cross-validation. Here's how it works, when to use it, and a complete implementation with Scikit-Learn.Fri, 07 Feb 2025 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/randomized-search-hyperparameter-tuning/https://rotunno.io/blog/randomized-search-hyperparameter-tuning/When your parameter space is too large for Grid Search, Randomized Search samples combinations efficiently. Here's how it works and when it outperforms the exhaustive alternative.Fri, 07 Feb 2025 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/fed-reserve-policy-fred-analysis/https://rotunno.io/blog/fed-reserve-policy-fred-analysis/A data-driven look at how U.S. monetary policy has evolved across Fed chairmanships — from Volcker's inflation shock therapy to Powell's pandemic-era pivots — using FRED economic data.Fri, 20 Sep 2024 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/r-iris-dataset-analysis/https://rotunno.io/blog/r-iris-dataset-analysis/A hands-on walkthrough of exploratory data analysis using R's built-in Iris dataset — aggregate functions, median comparisons, and what the numbers actually tell us about species differentiation.Wed, 18 Sep 2024 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/r-sequences-simulations-random/https://rotunno.io/blog/r-sequences-simulations-random/A practical guide to generating sequences, running simulations, and working with random numbers in R — covering seq(), sample(), runif(), and when each tool is the right one.Wed, 18 Sep 2024 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/leadership-lessons-self-awareness-eq/https://rotunno.io/blog/leadership-lessons-self-awareness-eq/Leadership isn't a title — it's a practice. Six lessons on self-awareness, conflict, stress, authenticity, values, and emotional intelligence that hold up under pressure.Wed, 11 Sep 2024 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/kroger-retail-data-strategy/https://rotunno.io/blog/kroger-retail-data-strategy/How Kroger turned grocery data into a competitive moat — from the SSOT-MVOTs framework to Kroger Precision Marketing, 84.51°, and smart shelving technology.Tue, 10 Sep 2024 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/chipotle-order-trends-r/https://rotunno.io/blog/chipotle-order-trends-r/A hands-on walkthrough using real Chipotle order data — loading, aggregating, and visualizing purchase patterns with R and ggplot2.Mon, 26 Aug 2024 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/coin-flip-simulation-r/https://rotunno.io/blog/coin-flip-simulation-r/Random sampling, reproducibility, subsetting, and counting outcomes — all through a simple coin flip simulation. The concepts here apply everywhere in data analysis.Mon, 26 Aug 2024 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/data-manipulation-r-winsorizing/https://rotunno.io/blog/data-manipulation-r-winsorizing/Generate synthetic data, compute descriptive stats, filter by condition, and cap outliers using winsorization — the core data cleaning toolkit in base R.Sun, 25 Aug 2024 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/chartmetric-2023-music-industry/https://rotunno.io/blog/chartmetric-2023-music-industry/Over 1.3 million new artists, 17 million new tracks, and platforms that didn't exist a decade ago. Here's what Chartmetric's 2023 report reveals about where the industry is heading.Tue, 02 Jul 2024 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/music-revenue-streams-flow/https://rotunno.io/blog/music-revenue-streams-flow/From the moment a listener streams a song to the moment a songwriter cashes a check — here's the full map of how money moves through the music industry ecosystem.Tue, 02 Jul 2024 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/music-industry-revenue-streams/https://rotunno.io/blog/music-industry-revenue-streams/A data-driven breakdown of how money flows through the music industry — PROs, sound recordings, live performance revenue, streaming splits, and what artists actually keep.Tue, 13 Feb 2024 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/future-of-live-music/https://rotunno.io/blog/future-of-live-music/How direct ticket sales, the Live Nation monopoly, and Taylor Swift's Eras Tour are reshaping the live music industry — and what artists are doing to take back control.Sat, 10 Feb 2024 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/artistic-insights-2024/https://rotunno.io/blog/artistic-insights-2024/How the creative economy is evolving in 2024 — YouTube's $70B GDP contribution, declining trust in institutions, the rise of individual creators, and what data tells us about arts education outcomes.Thu, 01 Feb 2024 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/ghostbusters-philosophy-business/https://rotunno.io/blog/ghostbusters-philosophy-business/What a team of underprepared scientists with a proton pack taught me about showing up ready, building systems before you need them, and why preparedness is a professional strategy.Mon, 29 Jan 2024 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/regression-vs-classification/https://rotunno.io/blog/regression-vs-classification/Regression predicts a number. Classification predicts a category. The difference sounds simple, but it shapes everything — which algorithms to use, how to evaluate results, and what your model actually outputs.Fri, 21 Jul 2023 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)https://rotunno.io/blog/testing-interaction-main-effects/https://rotunno.io/blog/testing-interaction-main-effects/Main effects tell you what each variable does in isolation. Interaction effects tell you whether the combination matters. Here's how to test for both using Python's statsmodels.Fri, 21 Jul 2023 00:00:00 GMTchrisrotunno@icloud.com (Christopher A. Rotunno)