Black Box Explanation vs Explanation by Design#

Synonyms: Post-hoc vs Ante-hoc Explanations.

In brief#

The difference between Black Box Explanation (or Post-hoc Explanations) and Explanation by Design (or Ante-hoc Explanations) regards the ability to know and exploit the behaviour of the AI model. With a black box explanation, we pair the black box model with an interpretation the black box decisions or model, while in the second case, the strategy is to rely, by design, on a transparent model.

More in detail#

When we talk about Black Box Explanation, the strategy is to couple an AI with a black box model with an explanation method able to interpret the black box decisions. In the case of Explanation by Design (aka Transparency), the idea is to substitute the obscure model with a transparent model in which the decision process is accessible by design, i.e., explainability is inserted into a model from the very beginning.

Figure 8 depicts this distinction.

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Fig. 8 (Top) Black box explanation pipeline. (Bottom) Explanation by design pipeline. [1].#

Starting from a dataset X, the black box explanation idea is to maintain the high performance of the obscure model b used by the AI, which is allowed to be trained normally, and to use an explanation method f to retrieve an explanation e by reasoning over b and X. In such a way, we aim to reach both accuracy and the ability to gain some Kinds of Explanations. This kind of approach is the one more addressed nowadays in the XAI research field [1] [2] [3].

On the other hand, the explanation by design consists of directly designing a comprehensible model c over the dataset X, which is interpretable by design and returns an explanation e besides the prediction y. Thus, the idea is to use this transparent model directly in the AI system [5] [6]. In the literature, there are various models recognized to be interpretable. Examples include decision trees, decision rules, and linear models [7]. These models are considered easily understandable and interpretable for humans. However, nearly all of them sacrifice performance in favor of interpretability. In addition, they cannot be applied effectively on data types such as images or text, but only on tabular, relational data, i.e., tables.

Bibliography#

1

M.T. Ribeiro, S. Singh, and C. Guestrin. "why should I trust you?": explaining the predictions of any classifier. In SIGKDD. 2016.

2

Riccardo Guidotti, Anna Monreale, Dino Pedreschi, and Fosca Giannotti. Principles of Explainable Artificial Intelligence. Springer International Publishing, 2021.

3

S. M. Lundberg and S.-I. Lee. A unified approach to interpreting model predictions. In Advances in neural information processing systems, 4765–4774. 2017.

4

M. Craven and J. W. Shavlik. Extracting tree-structured representations of trained networks. In Advances in neural information processing systems, volume 8, 24–30. 1996.

5

C. Rudin. Stop explaining black box machine learning models for high stakes decisions and use interpretable models instead. Nature Machine Intelligence, 1(5):206–215, 2019.

6

C. Rudin and J. Radin. Why are we using black box models in ai when we don’t need to? A lesson from an explainable AI competition. Harvard Data Science Review, 2019.

7

A. A. Freitas. Comprehensible classification models: a position paper. ACM SIGKDD explorations newsletter, 15(1):1–10, 2014.

This entry was readapted from Guidotti, Monreale, Pedreschi, Giannotti. Principles of Explainable Artificial Intelligence. Springer International Publishing (2021) by Francesca Pratesi and Riccardo Guidotti.