Beyond Data — Investigative Data Journalist

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  • All Models Are Wrong!

    ”All models are wrong, but some are useful.” Charles Box

    MAR 27 SERGIO FETTER

  • What Universal Optmization Works Best? No-Free-Lunch Theorem

    There are hundreds, if not thousands, of algorithms and statistical methods. When I first started in this field, the first method I tried in every single dataset was K-means. It was my go-to algorithm.

    MAR 25 SERGIO FETTER

  • Unweighted and Weighted Logistic Regression Models

    Even after so many years, I still remember one of my very first logistic regression projects. I was so proud of it. Until my supervisor kicked it back and told me that I had to weigh it.

    MAR 19 SERGIO FETTER

  • The AI Bubble Nobody Wants to Talk About

    There isn't one day when I open the news or social media that I don't come across AI news.

    MAR 16 SERGIO FETTER

  • What Are Vector Embeddings?

    Is vector embedding one of those buzzwords in data science? What are they and why are they important? In short, they are decoders or translators, essential for machine learning.

    MAR 12 SERGIO FETTER

  • Why P-Values Don't Mean What Most People Think They Mean

    Very early in my PhD program, I began working with and testing hypotheses. One of the first challenges I had to overcome was understanding the p-value.

    MAR 12 SERGIO FETTER

  • What is Bias and Variance Tradeoff

    You don't want the model to over- or under-fit. You have to strive to find the right balance between the two. That is the bias-variance tradeoff.

    MAR 09 SERGIO FETTER

  • Why Data Science Projects Fail and How to Avoid It

    Not long ago, I sat with an apartment owner who had taken over 144 units. There were 15 vacant, 12 on move-out notice, and four evictions for the end of the month. If the notices and evictions were to go through, the occupancy rate would be at 78 percent.

    DEC 23 SERGIO FETTER

  • Amazon Ships Before You Order—Here's How Your Business Can Do the Same

    Amazon ships products before you order them. And it's been doing it for over a decade.

    DEC 09 SERGIO FETTER

  • Property Files #2: When the System Fails Everyone

    I debated whether to share this story. Evictions are one of the most difficult parts of property management—and one of the least understood or perceived as corporate greed. From the outside, it looks simple: the resident doesn't pay, the landlord kicks them out. Landlord wins, residents lose.

    DEC 02 SERGIO FETTER