Lusha Xu University of California, Riverside · Economics

GradQuant

Lead Consultant at the Graduate Quantitative Methods Center, UC Riverside — workshops and one-on-one methods consulting for graduate students across the university.

The RoleLead Consultant · 2025–2026

GradQuant is UC Riverside’s campus-wide center for quantitative and computational methods training. As Lead Consultant I work with graduate students from every school on campus — on their own data, at whatever stage they have reached.

  • Individual consultations and drop-in hours on statistics and programming
  • Developing and presenting workshops
  • Scheduling and coordinating part-time consultants
  • Building and maintaining the center’s teaching resources and website
  • Outreach: campus events, GradSuccess programming, and social media

WorkshopsHands-on sessions in Python, taught in Google Colab

Introduction to Python

~2 hours · no prior programming experience

Getting set up in Colab, then the essentials: variables and data types, strings and f-strings, lists, tuples and dictionaries, indexing and slicing, functions and modules, and plotting with matplotlib. The session closes with a mini project that pulls CPI and unemployment from FRED, computes year-over-year inflation, and fits a Phillips curve.

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Time Series Analysis

2 hours

Why time series breaks the OLS assumptions, and what to do about it. Trend, seasonality, cycles, shocks and structural breaks; stationarity, unit roots and the ADF test; seasonal decomposition; reading ACF and PACF to choose lag orders; estimating ARIMA and SARIMA, validating with Ljung–Box, and forecasting out of sample. Worked on U.S. real GDP and the airline passenger series.

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High-Dimensional Data: From Factor Models to Deep Learning

April 2026

Four strategies for forecasting with many correlated predictors, compared on a simulated macro dataset with three latent factors and sixty indicators: PCA and factor models (compression), partial least squares (supervised compression), Lasso (sparse selection), and neural networks (representation learning). Covers the estimation problem behind each method and how to evaluate them with out-of-sample RMSE, MAE and R² against an AR(1) benchmark.

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Large Language Models: Theory and Practice

First the mechanism — tokens, embeddings, positional encoding, attention, multi-head attention, encoder and decoder blocks, and what pretraining and post-training do to a model’s behavior. Then research practice: when an LLM beats a dictionary or a fine-tuned classifier and when it does not, calling an API reproducibly, grounding prompts in source text, and validating model output against hand-coded samples — demonstrated by scoring FOMC statements for hawkishness.

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ConsultationsAugust 2025 – June 2026

Thirty-six scheduled appointments and twelve drop-in sessions. The scheduled ones drew students from CNAS, CHASS, BCOE, the School of Public Policy, the School of Medicine and the Graduate School of Education — entomology, plant pathology, psychology, political science, computer science, materials science, public policy, economics and more. Twenty-one were doctoral students, nine master’s students, five postdoctoral researchers; fifteen were international students.

What we worked on
  • Mixed-effects and generalized linear mixed models — gamma, Tweedie, zero-inflated and hurdle specifications for count and skewed biological data
  • ANOVA (two-way, repeated measures) and nonparametric alternatives such as Kruskal–Wallis
  • Tests for variance and spread; distributional checks and corrections
  • Moderated mediation and structural equation models — identification, centering, interpretation
  • Machine learning coursework and applied final projects
  • Panel econometrics in Stata — nonstationarity, cointegration, error-correction models, difference-in-differences with staggered adoption
  • Dissertation formatting in LaTeX and Overleaf — templates, margins, front matter