Susan Lottridge

Author directory

2026

This study synthesizes feature-based and pairwise-comparison approaches to item parameter modeling by using an LLM as an investigator of item characteristics and a judge of relative item parameters. The proposed framework aims to improve recovery of item parameter rankings and predictions while providing insight into factors associated with the parameters.
Fine-grained formative writing feedback needs dense, standards-aligned labels that human annotation cannot supply at scale. We describe a multi-agent LLM pipeline producing verified silver labels, and then train small deterministic transformer scorers. On a Grade 5 pilot these reach Cohen’s 𝜅 up to 0.92 on conventions.
We present a production system for hierarchical analytic writing feedback that uses frontier LLMs to generate training data for fine-tuned transformer models. Applied to Grade 5 opinion essays, the system scores 5 competency dimensions and 31 binary feedback codes, achieving agreement approaching inter-rater levels from training sets of 300–500 essays.
We compare long-context architectures (ModernBERT, Longformer, and causal and bidirectional Mamba) for data-efficient automated essay scoring across four training sizes on ASAP-2. Bidirectional Mamba matches the transformers. Deployment readiness depends more on label quantity (rising from 60% to 84% as training grows from 128 to 512 essays) than on backbone choice.

2025

Item (question) difficulties play a crucial role in educational assessments, enabling accurate and efficient assessment of student abilities and personalization to maximize learning outcomes. Traditionally, estimating item difficulties can be costly, requiring real students to respond to items, followed by fitting an item response theory (IRT) model to get difficulty estimates. This approach cannot be applied to the cold-start setting for previously unseen items either. In this work, we present SMART (Simulated Students Aligned with IRT), a novel method for aligning simulated students with instructed ability, which can then be used in simulations to predict the difficulty of open-ended items. We achieve this alignment using direct preference optimization (DPO), where we form preference pairs based on how likely responses are under a ground-truth IRT model. We perform a simulation by generating thousands of responses, evaluating them with a large language model (LLM)-based scoring model, and fit the resulting data to an IRT model to obtain item difficulty estimates. Through extensive experiments on two real-world student response datasets, we show that SMART outperforms other item difficulty prediction methods by leveraging its improved ability alignment.
We investigate the reliability of two scoring approaches to early literacy decoding items, whereby students are shown a word and asked to say it aloud. Approaches were rubric scoring of speech, human or AI transcription with varying explicit scoring rules. Initial results suggest rubric-based approaches perform better than transcription-based methods.
We present preliminary evidence on the impact of a NLP-based writing feedback tool, Write-On with Cambi! on students’ argumentative writing. Students were randomly assigned to receive access to the tool or not, and their essay scores were compared across three rubric dimensions; estimated effect sizes (Cohen’s d) ranged from 0.25 to 0.26 (with notable variation in the average treatment effect across classrooms). To characterize and compare the groups’ writing processes, we implemented an algorithm that classified each revision as Appended (new text added to the end), Surface-level (minor within-text corrections to conventions), or Substantive (larger within-text changes or additions). We interpret within-text edits (Surface-level or Substantive) as potential markers of metacognitive engagement in revision, and note that these within-text edits are more common in students who had access to the tool. Together, these pilot analyses serve as a first step in testing the tool’s theory of action.
The study introduces novel approaches for fine-tuning pre-trained LLMs to predict item response theory parameters directly from item texts and structured item attribute variables. The proposed methods were evaluated on a dataset over 1,000 English Language Art items that are currently in the operational pool for a large scale assessment.