*Natural Language to Visualization* (NL2Vis) seeks to convert natural-language descriptions into visual representations of given tables, empowering users to derive insights from large-scale data. Recent advancements in *Large Language Models* (LLMs) show promise in automating code generation to transform tabular data into accessible visualizations. However, they often struggle with complex queries that require reasoning across multiple tables. To address this limitation, we propose a collaborative agent workflow, termed **nvAgent**, for NL2Vis. Specifically, **nvAgent** comprises three agents: a processor agent for database processing and context filtering, a composer agent for planning visualization generation, and a validator agent for code translation and output verification. Comprehensive evaluations on the new VisEval benchmark demonstrate that **nvAgent** consistently surpasses state-of-the-art baselines, achieving a 7.88% improvement in single-table and a 9.23% improvement in multi-table scenarios. Qualitative analyses further highlight that **nvAgent** maintains nearly a 20% performance margin over previous models, underscoring its capacity to produce high-quality visual representations from complex, heterogeneous data sources. All datasets and source code are available at: [https://github.com/geliang0114/nvAgent](https://github.com/geliang0114/nvAgent).

This study examines whether NLP transfer learning techniques, specifically BERT, can be used to develop prompt-generic AES models for practice writing tests. Findings reveal that fine-tuned DistilBERT, without further pre-training, achieves high agreement (QWK ≈ 0.89), enabling scalable, robust AES models in statewide K-12 assessments without costly supplementary pre-training.

Generalizability Theory with entropy-derived stratification optimized automated essay scoring reliability. A G-study decomposed variance across 14 encoders and 3 seeds; D-studies identified minimal ensembles achieving G ≥ 0.85. A hybrid of one medium and one small encoder with two seeds maximized dependability per compute cost. Stratification ensured uniform precision across