Cross-validation challenges and best practices
LLMs present unique challenges for cross-validation due to their scale and the nature of their training data. Here are some key challenges:
- Data contamination: Avoiding test set overlap with pre-training data is difficult given the vast and diverse web data LLMs are trained on, making it hard to ensure a truly unseen validation set
- Computational cost: Traditional methods such as k-fold cross-validation are often infeasible due to the immense computational resources required for models of this scale
- Domain shift: LLMs may show inconsistent performance when exposed to data from underrepresented or entirely new domains, complicating the evaluation of generalizability
- Prompt sensitivity: The performance of LLMs can vary significantly based on subtle differences in prompt wording, adding another layer of variability to the validation process
Based on these challenges, here are some best practices for LLM cross-validation...