  Modern ML systems ingest data aggregated from diverse sources, such as
synthetic, human-annotated, and live customer traffic. Understanding
\textit{which} examples are important to the performance of a learning
algorithm is crucial for efficient model training. Recently, a growing body of
literature has given rise to various "influence scores," which use training
artifacts such as model confidence or checkpointed gradients to identify
important subsets of data. However, these methods have primarily been developed
in computer vision settings, and it remains unclear how well they generalize to
language-based tasks using pretrained models.
  In this paper, we explore the applicability of influence scores in language
classification tasks. We evaluate a diverse subset of these scores on the SNLI
dataset by quantifying accuracy changes in response to pruning training data
through random and influence-score-based sampling. We then stress-test one of
the scores -- "variance of gradients" (VoG) from Agarwal et al. (2022) -- in an
NLU model stack that was exposed to dynamic user speech patterns in a voice
assistant type of setting. Our experiments demonstrate that in many cases,
encoder-based language models can be finetuned on roughly 50% of the original
data without degradation in performance metrics. Along the way, we summarize
lessons learned from applying out-of-the-box implementations of influence
scores, quantify the effects of noisy and class-imbalanced data, and offer
recommendations on score-based sampling for better accuracy and training
efficiency.
