AIC vs BIC: Difference and Comparison

Key Takeaways

1. Definition: AIC (Akaike Information Criterion) and BIC (Bayesian Information Criterion) are both statistical measures used in model selection and statistical modeling to assess the trade-off between model fit and complexity. They are used to compare different models and select the one that best explains the data.
2. Purpose: AIC and BIC serve similar purposes but use slightly different approaches. AIC seeks to estimate the relative quality of statistical models for a given dataset and helps select models that minimize information loss. BIC, on the other hand, penalizes model complexity more heavily, which can result in the selection of simpler models.
3. Selection Criteria: In general, when comparing models using AIC and BIC, lower values indicate a better fit. However, BIC tends to prefer simpler models more strongly than AIC. Therefore, if there is a trade-off between model fit and complexity, BIC is more likely to favor a simpler model compared to AIC.
4. In summary, AIC and BIC are statis

What is AIC?

The Akaike Information Criterion (AIC) is a statistical measure commonly used in model selection and evaluation, particularly in regression analysis and predictive modeling. It was developed by the Japanese statistician Hirotugu Akaike.

AIC is a widely used statistical tool for comparing models and balancing model fit and complexity. It’s a valuable tool in model selection, helping researchers and analysts choose the most appropriate model for their data.

What is BIC?

The Bayesian Information Criterion (BIC), or the Schwarz criterion, is a statistical measure used for model selection and evaluation. It’s similar in purpose to the Akaike Information Criterion (AIC) but has some distinct characteristics.

The Bayesian Information Criterion (BIC) is a tool for model selection that emphasizes model simplicity more strongly than AIC. It’s particularly useful when dealing with smaller datasets and can help prevent the inclusion of unnecessary parameters in statistical models.

Difference Between AIC and BIC

1. AIC is based on the maximum likelihood estimation of the model parameters. It is calculated using the formula AIC = -2 * log-likelihood + 2 * number of parameters. Conversely, BIC also uses the likelihood but includes a penalty for the number of parameters. It is calculated as BIC = -2 * log-likelihood + log(sample size) * number of parameters.
2. AIC tends to favor more complex models to some extent, as it penalizes fewer parameters than BIC. BIC imposes a stronger penalty for model complexity. It strongly discourages the inclusion of unnecessary parameters, which can lead to simpler models.
3. When choosing between AIC models, you would select the model with the lowest AIC value. When using BIC, you would choose the model with the lowest BIC value.
4. AIC is derived from information theory and the likelihood function. It is based on the principle of minimizing information loss. BIC is based on Bayesian principles and incorporates a Bayesian perspective on model selection. It aims to find the model that is most probable given the data.
5. AIC is used when there is a focus on model selection and the trade-off between model fit and complexity needs to be considered. It is useful in a wide range of statistical analyses. BIC is particularly useful when there’s a need to strongly penalize complex models, such as in situations with limited data, where simplicity is highly valued, or in Bayesian model selection.

Comparison Between AIC and BIC

Parameters of Comparison	AIC	BIC
Weight on Simplicity	AIC is relatively more lenient regarding model complexity.	BIC strongly favors simpler models and penalizes complexity more.
Asymptotic Consistency	AIC is not inherently tied to Bayesian modeling and can be used in frequentist and Bayesian contexts.	AIC is consistent, meaning it selects the true model as the sample size grows to infinity.
Overfitting Prevention	AIC can be useful when you want to avoid severe overfitting but are open to somewhat more complex models.	AIC is consistent and selects the true model as the sample size grows to infinity.
Use in Bayesian Modeling	BIC is asymptotically consistent but focuses more on model parsimony even in large samples.	BIC has a stronger connection to Bayesian methods and is used in Bayesian model selection due to its Bayesian underpinnings.
Information Criteria Interpretation	AIC’s primary interpretation is that it approximates the expected Kullback-Leibler divergence between the true model and the estimated model.	BIC prevents overfitting by heavily penalizing complex models, making it suitable for smaller datasets.

References

1. https://journals.sagepub.com/doi/abs/10.1177/0049124103262065
2. https://psycnet.apa.org/record/2012-03019-001

Last Updated : 25 November, 2023