Portrait of Yikai (EK) Lu

Assistant Professor of Quantitative Methods in Education

Department of Educational Psychology
University of Minnesota–Twin Cities

My research focuses on psychometrics, machine learning and AI in education, and visualization.

ekl@umn.edu GitHub

Research

Research interests

My work combines psychometrics, machine learning, and visual analytics in educational research.

01

Statistical Modeling of Innovative Item Types

Models and adaptive testing methods for assessments that capture richer response behavior, including multiple-choice, multiple-attempt items.

Examples: sequential item response models and adaptive testing for multiple-attempt items.

Item category response functions for the number of attempts across ability levels
Item category response functions for the number of attempts.
Multiple attemptsItem response theoryAdaptive testing
02

Machine Learning and AI in Education

Interpretable Knowledge Tracing with Measurement emphasis

Incorporating process data, curricula information, and temporal effects into knowledge-tracing models, with emphasis on interpreting how those inputs affect learning estimates.

Examples: HawkesIRT and knowledge tracing with process and curricula information.

HawkesIRT visualization showing predicted responses and latent knowledge while accounting for time between attempts
HawkesIRT traces predicted responses and latent knowledge by taking into account time between attempts.

Applications of ML/AI to quantitative methods

Using language, vision, and explainable AI to study items, response processes, and psychometric evidence.

Examples: multimodal item parameter prediction and LLM-based DIF analysis.

03

Visualization

Interactive visual analytics that help researchers understand statistical models and communicate complex findings.

Example: FAVis paper and interactive demo.

Publications

Selected publications

For a complete publication list, see my CV.

2026

ACM Learning @ Scale

HawkesIRT: Interpretable and efficient knowledge tracing via temporal item effects and item response theory

Lu, Y.

View publication
2026

Journal of Educational and Behavioral Statistics

Adaptive testing for multiple-choice, multiple-attempt test items

Lu, Y. & Cheng, Y.

View publication
2026

Educational and Psychological Measurement

Multimodal Test Item Parameter Prediction From Text, Images, and Metadata: Fusing Together AI Vision and Language Models

Maeda, H. & Lu, Y.

View publication
2025

Psychometrika

A family of sequential item response models for multiple-choice, multiple-attempt test items

Lu, Y., Fowler, J. & Cheng, Y.

View publication

Software

Open-source tools developed alongside my research.

FAVis

Visual analytics of factor analysis for psychological research.

DemoSource

sirtmm

R package for sequential item response models for multiple-choice, multiple-attempt test items.

Source

Teaching

University of Minnesota

EPSY 3264

Basic and Applied Statistics

Spring and Fall 2026

EPSY 8251

Statistical Methods in Education I

Fall 2025

Appointments and education

2025—present

Assistant Professor

Department of Educational Psychology, Quantitative Methods in Education
University of Minnesota–Twin Cities

2025

Ph.D. in Psychology and Computer Science and Engineering

University of Notre Dame · Joint program

2024 · 2023

M.S., Computer Science · M.S., Applied Computational & Mathematical Statistics

University of Notre Dame

2019

B.S., Computer Science · B.S., Psychology

University of Minnesota–Twin Cities · Statistics minor · High distinction

Contact

ekl@umn.edu