Dual Interpretation of Machine Learning Forecasts

Fuente: arXiv
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Autori principali: Coulombe, Philippe Goulet, Goebel, Maximilian, Klieber, Karin
Natura: Preprint
Pubblicazione: 2024
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author Coulombe, Philippe Goulet
Goebel, Maximilian
Klieber, Karin
author_facet Coulombe, Philippe Goulet
Goebel, Maximilian
Klieber, Karin
contents Machine learning predictions are typically interpreted as the sum of contributions of predictors. Yet, each out-of-sample prediction can also be expressed as a linear combination of in-sample values of the predicted variable, with weights corresponding to pairwise proximity scores between current and past economic events. While this dual route leads nowhere in some contexts (e.g., large cross-sectional datasets), it provides sparser interpretations in settings with many regressors and little training data-like macroeconomic forecasting. In this case, the sequence of contributions can be visualized as a time series, allowing analysts to explain predictions as quantifiable combinations of historical analogies. Moreover, the weights can be viewed as those of a data portfolio, inspiring new diagnostic measures such as forecast concentration, short position, and turnover. We show how weights can be retrieved seamlessly for (kernel) ridge regression, random forest, boosted trees, and neural networks. Then, we apply these tools to analyze post-pandemic forecasts of inflation, GDP growth, and recession probabilities. In all cases, the approach opens the black box from a new angle and demonstrates how machine learning models leverage history partly repeating itself.
format Preprint
id arxiv_https___arxiv_org_abs_2412_13076
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Dual Interpretation of Machine Learning Forecasts
Coulombe, Philippe Goulet
Goebel, Maximilian
Klieber, Karin
Econometrics
Machine Learning
Machine learning predictions are typically interpreted as the sum of contributions of predictors. Yet, each out-of-sample prediction can also be expressed as a linear combination of in-sample values of the predicted variable, with weights corresponding to pairwise proximity scores between current and past economic events. While this dual route leads nowhere in some contexts (e.g., large cross-sectional datasets), it provides sparser interpretations in settings with many regressors and little training data-like macroeconomic forecasting. In this case, the sequence of contributions can be visualized as a time series, allowing analysts to explain predictions as quantifiable combinations of historical analogies. Moreover, the weights can be viewed as those of a data portfolio, inspiring new diagnostic measures such as forecast concentration, short position, and turnover. We show how weights can be retrieved seamlessly for (kernel) ridge regression, random forest, boosted trees, and neural networks. Then, we apply these tools to analyze post-pandemic forecasts of inflation, GDP growth, and recession probabilities. In all cases, the approach opens the black box from a new angle and demonstrates how machine learning models leverage history partly repeating itself.
title Dual Interpretation of Machine Learning Forecasts
topic Econometrics
Machine Learning
url https://arxiv.org/abs/2412.13076