A Hypothesis-Driven Framework for the Analysis of Self-Rationalising Models
This addresses the need for better evaluation of LLM explanation faithfulness, but it is incremental as it builds on existing methods for analyzing model decisions.
The authors tackled the problem of assessing the faithfulness of self-rationalizing LLM explanations by proposing a hypothesis-driven statistical framework using Bayesian networks to model decision processes, and found that the resulting models did not show strong similarity to GPT-3.5.
The self-rationalising capabilities of LLMs are appealing because the generated explanations can give insights into the plausibility of the predictions. However, how faithful the explanations are to the predictions is questionable, raising the need to explore the patterns behind them further. To this end, we propose a hypothesis-driven statistical framework. We use a Bayesian network to implement a hypothesis about how a task (in our example, natural language inference) is solved, and its internal states are translated into natural language with templates. Those explanations are then compared to LLM-generated free-text explanations using automatic and human evaluations. This allows us to judge how similar the LLM's and the Bayesian network's decision processes are. We demonstrate the usage of our framework with an example hypothesis and two realisations in Bayesian networks. The resulting models do not exhibit a strong similarity to GPT-3.5. We discuss the implications of this as well as the framework's potential to approximate LLM decisions better in future work.