https://data-awesome.com/blog Writing on data analytics, Alteryx, AI and the career around them, from ten years leading analytics in airline operations. en-us racine.isacar@gmail.com (Isacar Racine) racine.isacar@gmail.com (Isacar Racine) Mon, 27 Apr 2026 00:00:00 GMT https://data-awesome.com/blog/regression-trap-index https://data-awesome.com/blog/regression-trap-index Fifteen ways regression output gets misread, with the symptom, what it actually means, and how to check. Every one came from a real model. Mon, 27 Apr 2026 00:00:00 GMT racine.isacar@gmail.com (Isacar Racine) regressionstatisticsmodel-diagnostics https://data-awesome.com/blog/regression-coefficient-sign-flip https://data-awesome.com/blog/regression-coefficient-sign-flip Alone it reads -0.0054. With seven other predictors, +0.0154. Both significant. Why hunting for the guilty variable is the wrong instinct. Mon, 20 Apr 2026 00:00:00 GMT racine.isacar@gmail.com (Isacar Racine) regressionstatisticsmodel-diagnostics https://data-awesome.com/blog/regression-coefficient-not-causal https://data-awesome.com/blog/regression-coefficient-not-causal The smoker coefficient is $24,330. That does not mean quitting saves anyone $24,330, and no amount of significance will make it mean that. Mon, 13 Apr 2026 00:00:00 GMT racine.isacar@gmail.com (Isacar Racine) regressionstatisticsmodel-diagnostics https://data-awesome.com/blog/variable-selection-regularization https://data-awesome.com/blog/variable-selection-regularization Ridge, lasso and elastic net returned identical test error, to the last digit. The reason is a mistake hiding in a workflow you have copied. Mon, 06 Apr 2026 00:00:00 GMT racine.isacar@gmail.com (Isacar Racine) regressionmachine-learningstatisticsr https://data-awesome.com/blog/logistic-regression-reading-output https://data-awesome.com/blog/logistic-regression-reading-output Your model says 1.60. That cannot be a probability. Four things that go wrong reading logistic output, and none of them throw an error. Mon, 30 Mar 2026 00:00:00 GMT racine.isacar@gmail.com (Isacar Racine) regressionstatisticsr https://data-awesome.com/blog/regression-diagnostics-outliers-multicollinearity https://data-awesome.com/blog/regression-diagnostics-outliers-multicollinearity I removed 53 outliers. R-squared rose from 0.818 to 0.856 and the model got worse. Every number that improved ignored the rows I deleted. Mon, 23 Mar 2026 00:00:00 GMT racine.isacar@gmail.com (Isacar Racine) regressionmodel-diagnosticsstatisticsr https://data-awesome.com/blog/multiple-regression-interpreting-coefficients https://data-awesome.com/blog/multiple-regression-interpreting-coefficients Your slide says $368. A colleague who ran the same data says $422. Four ways a regression coefficient means less than it appears to. Mon, 16 Mar 2026 00:00:00 GMT racine.isacar@gmail.com (Isacar Racine) regressionstatisticsr https://data-awesome.com/blog/simple-linear-regression-assumptions https://data-awesome.com/blog/simple-linear-regression-assumptions One broken assumption ruins your coefficients; the other three only ruin your p-values. Knowing which decides whether you scrap the model. Mon, 09 Mar 2026 00:00:00 GMT racine.isacar@gmail.com (Isacar Racine) regressionstatisticsmodel-diagnostics https://data-awesome.com/blog/linear-regression-explained-simply https://data-awesome.com/blog/linear-regression-explained-simply Everyone nods when it comes up in a meeting. What a coefficient actually is, how to read the output, and why the obvious answer was wrong. Mon, 02 Mar 2026 00:00:00 GMT racine.isacar@gmail.com (Isacar Racine) regressionstatisticsanalytics