On 15 OOD datasets spanning 8 NLU tasks (sentiment, NLI, paraphrase, entailment, similarity, grammar), ChatGPT achieves 66.67% average accuracy in zero-shot and 72.28% with 16-shot ICL, compared to 86.83% human performance. Llama-2-7b-chat achieves 55.92% zero-shot and 58.54% with 16-shot ICL. The gap is particularly severe on MNLI (ChatGPT 41.54%, Llama-2 34.30%) and CoLA (ChatGPT 39.05%, Llama-2 6.94%). The authors note that even with 16-shot ICL, performance remains far below the SLM Electra-large (79.86%).
The OOD setting follows GLUE-X protocol; in-context examples are drawn from in-domain data while test sets are from different domains. Data sizes differ between ChatGPT (43,728 instances) and Llama-2 (37,438 instances) due to prompt length constraints.