CoverICL: Selective Annotation for In-Context Learning via Active Graph Coverage

In-context learning (ICL) adapts Large Language Models (LLMs) to new tasks, without requiring any parameter updates, but few annotated examples as input. In this work, we investigate selective annotation for ICL, where there is a limited budget for annotating examples, similar to low-budget active learning (AL). Although uncertainty-based selection is unreliable with few annotated data, we present COVERICL, an adaptive graph-based selection algorithm, that effectively incorporates uncertainty sampling into selective annotation for ICL. First, COVERICL builds a nearestneighbor graph based on the semantic similarity between candidate ICL examples. Then, COVERICL employs uncertainty estimation by the LLM to identify hard examples for the task. Selective annotation is performed over the active graph of the hard examples, adapting the process to the particular LLM used and the task tackled. COVERICL selects the most representative examples by solving a Maximum Coverage problem, approximating diversitybased sampling. Extensive experiments on ten datasets and seven LLMs show that, by incorporating uncertainty via coverage on the active graph, COVERICL (1) outperforms existing AL methods for ICL by 2-4.6% accuracy points, (2) is up to 2× more budget-efficient than SOTA methods for low-budget AL, and (3) generalizes better across tasks compared to non-graph alternatives.