Sam Zhang

Sam Zhang's Homepage

I am an Applied Complexity postdoc at the Santa Fe Institute, and starting in Fall 2025, an Assistant Professor of Statistics affiliated with the Vermont Complex Systems Institute at the University of Vermont.

I received my PhD in Applied Mathematics from the University of Colorado Boulder, advised by Aaron Clauset and Dan Larremore, where I was supported by an NSF Graduate Research Fellowship. During my PhD, I worked as a PhD research intern with the MSR NYC Computational Social Science group and the Human Rights Data Analysis Group.

my email is shimian dot my last name at gmail.com

More about me here.

Pronouns: he/him.

Link to CV

Google Scholar

Github

mastodon - bluesky - twitter

Upcoming

June 2025: Attending the Collective Social Phenomena: Dynamics and Data workshop at The Casa Matemática Oaxaca, ICSSI in Copenhagen, and an SFI-DeepMind roundtable in London.
August 2025: Starting at the University of Vermont.
December 2025: Co-organizing an SFI group on the historical evolution of human rights with David Wolpert.

News

Spring 2025: Proud to be an inaugural US Research Software Sustainability Institute Early-Career Fellow. Gave talks at the COP30 Climate Week in Panama (virtually), SIAM Dynamical Systems in Denver, the Social Aspects of Science and Innovation Workshop at Mizzou, at Pareto.ai in San Francisco, and at the Data and Democracy Lab's Structural Democracy Seminar. Attended an SFI working group on the energy grid. Visited the Human Rights Data Analysis Group.
Winter 2025: Gave a talk for a joint seminar at the Nationwide Children's Hospital and The Ohio State University. Spent February at Cornell University visiting Moon Duchin.
Fall 2024: Started my postdoc at the Santa Fe Institute. Talks at the Network Science Institute, UCL-UNIL ReproducibiliTea, UVM MassMutual Center of Excellence in Complex Systems and Data Science, as well as an SFI working group on Emergent Engineering. New paper led by Matt Hardy in the International Journal of Forecasting.

Publications

Also see [CV] or [Google Scholar].

‡ indicates alphabetical authorship.

An illusion of predictability in scientific results: Even experts confuse inferential uncertainty and outcome variability.

S. Zhang, P.R. Heck, M.N. Myers, C.F. Chabris, D.G. Goldstein, & J.M. Hofman. PNAS, 120(33): e2302491120 (2023).

[Carl Bergstrom's kind words about our paper]
Scientific productivity as a random walk.

S. Zhang, N. LaBerge, S.F. Way, D.B. Larremore, & A. Clauset. Submitted (2023).
Labor advantages drive the greater productivity of faculty at elite universities.

S. Zhang, K.H. Wapman, D.B. Larremore, & A. Clauset. Science Advances, 8(46) (2022).
Improving out-of-population prediction: The complementary effects of model assistance and judgmental bootstrapping

M. D. Hardy, S. Zhang, J. Hullman, J. M. Hofman, D. G. Goldstein. International Journal of Forecasting (2024).
Rush-hour-and-a-half: traffic is spreading out post-lockdown.

Matthew W Bhagat-Conway, S. Zhang. PLOS ONE, 18(9): e0290534 (2023).
Formalizing tenure of Indigenous lands improved forest outcomes in the Atlantic Forest of Brazil.

Rayna Benzeev, S. Zhang, Marcelo Rauber, Eric A Vance, Peter Newton. PNAS Nexus, 2: pgac287 (2023).
Gender and retention patterns among U.S. faculty.

Katie Spoon, Nicholas LaBerge, K Hunter Wapman, S. Zhang, Allison C Morgan, Mirta Galesic, Daniel B Larremore, Aaron Clauset. Science Advances, 9(42) (2023).
Quantifying hierarchy and dynamics in U.S. faculty hiring and retention.

K.H. Wapman, S. Zhang, A. Clauset, & D.B. Larremore. Nature, 610(7930): 120-127 (2022).
Untangling the network effects of productivity and prominence among scientists.

Weihua Li, S. Zhang, Zhiming Zheng, Skyler J Cranmer, Aaron Clauset. Nature Communications, 13: 4907 (2022).
Subfield prestige and gender inequality in computing.

Nicholas LaBerge, K Hunter Wapman, Allison C Morgan, S. Zhang, Daniel B Larremore, Aaron Clauset. Communications of the ACM, 65(12): 46-55 (2022).
‡ Visualizing and Unfolding Nets of 4-Polytopes.

Satyan L Devadoss, Matthew S Harvey, S. Zhang. 38th International Symposium on Computational Geometry (SoCG 2022).
Optimizing prevalence estimates for a novel pathogen by reducing uncertainty in test characteristics.

Daniel B Larremore, Bailey K Fosdick, S. Zhang, Yonatan H Grad. Epidemics, 41 (2022).
Estimating SARS-CoV-2 seroprevalence and epidemiological parameters with uncertainty from serological surveys.

Daniel B Larremore, Bailey K Fosdick, Kate M Bubar, S. Zhang, Stephen M Kissler, C Jessica E Metcalf, Caroline O Buckee, Yonatan H Grad. eLife, 10: e64206 (2021).

[+] Show more publications

Visualizations

I was drawn to study math because I found it to be beautiful. I hope I can share some of that beauty through these interactive visualizations. I made many of these visualizations to learn the concepts myself, but occasionally they are also part of larger projects. Note: many of these visualizations only work on desktop.

An illusion of predictability in scientific results

Even experts think / that well-estimated means / are certain outcomes. (Haiku summary due to MSR poets Dan and Jake). Click the thumbnail for a mini-explainer.

An illusion of predictability in scientific results

Sam Zhang, Patrick R Heck, Michelle Meyer, Christopher F Chabris, Daniel G Goldstein, Jake M Hofman PNAS, 2023 [paper]

[link] [source]

Elliptic curves and traveling wave solutions to the KdV equations

View traveling wave solutions to the KdV equations associated with (points of) elliptic curves.

[link] [source]

Ridge unfolding polytopes

Unfold 4-dimensional polytopes using their spanning trees.

Visualizing and unfolding nets of 4-polytopes

Satyan L Devadoss, Matthew S Harvey, Sam Zhang SoCG, 2022 [paper]

[link] [source]

Bayesian inference for COVID-19 testing

My brief foray into epidemiology at the start of COVID-19. Bayesian methods and interactive tools for informing COVID-19 surveillance testing strategies.

Estimating SARS-CoV-2 seroprevalence and epidemiological parameters with uncertainty from serological surveys

Daniel B Larremore, Bailey K Fosdick, Kate M Bubar, Sam Zhang, Stephen M Kissler, C Jessica E Metcalf, Caroline O Buckee, Yonatan H Grad eLife, 2021 [paper]

Optimizing prevalence estimates for a novel pathogen by reducing uncertainty in test characteristics

Daniel B Larremore, Bailey K Fosdick, Sam Zhang, Yonatan H Grad Epidemics, 2022 [paper]

[link] [link] [link] [link] [source]

Curve shortening

Deform a curve with a discrete curve shortening flow.

[link] [fullscreen] [source]

A catastrophe machine

Move the center of gravity of a wedge balancing on a table, and observe its corresponding catastrophe surface.

[link] [fullscreen] [source]

Linear regression, the old fashioned way

Perform ordinary least squares through a set of points with nails, springs, sleeves, and a frictionless rod.

[link] [fullscreen] [source]

A moduli space for triangles

A solution to a problem by Lewis Carroll using a clever moduli space. For fun, pick points on the moduli space, and watch triangles deform between them along geodesics.

[link] [fullscreen] [source]

The cross-section of a cylinder is an ellipse

A classical proof that the cross-section of a cylinder is an ellipse. I have no idea why, but this is the most popular blog post on my website.

[link] [fullscreen]

Whitney's Umbrella

First steps in visualizing 3d mathematics using javascript. A famous surface with a cuspidal point.

[link] [fullscreen]

Voronoizer bookmarklet

Draw a Voronoi diagram over any webpage with this bookmarklet.

[link] [source]

Voronoize this page!

This page has a Voronoi diagram drawn over it, with link and input HTML elements as points.

[link] [source]

Treasure hunting

You have been given flawed instructions for finding treasure on an island, but geometry may be able to help.

[link] [source]

An ascii implicit function plotter

Plot an elliptic curve (or any implicit function) using ASCII art!

[link] [source]

Hypocycloids

What happens if you rotate a smaller circle inside of a larger circle?

[link] [source]

Cats on ladders

A cat is sitting on a ladder leaning against the wall, and the ladder slips. What shape does the cat draw through the air?

[link] [source]

A network look at integer sequences

The Online Encyclopedia of Integer Sequences (OEIS) from a 10,000 foot view.

[link]

A visualization of a geometric bound on convex hulls

A lemma that bounds the size of a convex hull of points based off circles centered at those points.

[link] [source]

Building a municipal land use code search engine using a graph of word embeddings

Using the geometry of language to help permit-seekers find the right municipal land use codes.

[link]