Research


Statistical methods in invertebrate paleontology


Mass extinctions and the Signor-Lipps effect. When a collection of taxa (e.g., species of dinosaurs or ammonites) are killed off simultaneously in a mass extinction, their last occurrences in the fossil record may nonetheless give the impression of a gradual extinction, due to the incompleteness of the fossil record (the Signor-Lipps effect). I develop methods for testing whether a mass (sudden) extincton has occurred, and for estimating the position and duration of such an extinction. I also study the related topic of placing confidence intervals on stratigraphic ranges, i.e., estimating the time of extinction of a taxon based on its fossil record.

Evolutionary trends. Large-scale trends in the history of life (such as increase in body size, a.k.a. "Cope's Rule") may be a result of driven mechanisms (e.g., selection) or passive mechanisms (e.g., diffusion away from a lower bound). Several tests have been developed to categorize a trend as either driven or passive, but real trends are likely to be a combination of both types. I have developed a new method, the Analysis of Skewness, to quantify the extent to which a trend is a combination of driven and passive trends. I also study trends in the maximum size attained by life on earth over time, and ways of displaying and characterizing large-scale trends.

Macroevolution. Using statistical analysis and paleontological databases, I study large-scale questions about the history of life. Sample questions include: (1) Are mass extinctions merely larger manifestations of processes responsible for background extinction, or are they a fundamentally different phenomenon? (2) How many kinds of dinosaurs ever lived, and were dinosaurs already declining before an impact at the end of the Cretaceous Period caused their ultimate extinction? (3) Are observed extinction rates in mass extinctions a reliable guide to the severity of the triggering mechanism? That is, does a higher extinction rate indicate a more severe cause, or can factors such as Simpson's paradox make such an inference misleading?

Dynamics of extinction in food webs. The end-Permian mass extinction was the most severe in the history of life, but its causes remain enigmatic. With Peter Roopnarine of the California Academy of Sciences and Ken Angielczyk of the Field Museum, I study the dynamics of extinction in terrestrial ecosystems during the Permian. Using models of Permian food webs, we explore how the extinction of primary producers (e.g. green plants) could have led to the collapse of terrestrial ecosystems. More generally, we study factors leading to stability or instability in ecosystems.


More information:   Publications   |   Lab members and collaborators   |   Grant funding   |   Outreach   |   Media coverage   |   Talks

Reearch profiles:   ResearchGate   |   Google Scholar


Other areas of interest:

Statistical graphics and visualization. I am interested in how to effectively visualize high-dimensional datasets using graphical methods such as parallel axis plots and data image plots, and more generally in principles of effective graphical representation and communication.

Statistical methods in baseball research, also known as sabermetrics. I am interested in the analysis of managerial strategies (featured in the New York Times and the Philadelphia Inquirer; also see here for additional media coverage). My MS thesis was on a Markov Chain model for baseball lineups and player evaluation, with advisor Michael Stein. Read an interview with me on the growing use of statistical analysis in baseball.


Opportunities for students: I often have openings for student researchers for projects on statistical paleontology during the school year or the summer. During the school year, students can receive course credit (independent study/directed reading). During the summer, I sometimes have funding from the National Science Foundation, or students may apply for funding from Swarthmore College. Please email me if you are interested. Due to funding restrictions, eligibility is usually limited to Swarthmore students. The preferred prerequisites are Stat 61 and CS 21 (or equivalent), but some combination of Stat 11, Stat 31, Bio 2, or other experience may suffice as well. No paleontology background is necessary. Learn more about projects and publications by previous students.




Teaching


Courses at Swarthmore College
Stat 1: Statistical Thinking
Stat 11: Statistical Methods
Stat 21: Quantitative Paleobiology New course!
Stat 31: Data Analysis and Visualization
Stat 61: Probability and Mathematical Statistics I
Stat 111: Probability and Mathematical Statistics II seminar

View information on my previous courses and course evaluations at Stanford, Harvard, Williams, and The University of Chicago.

I was awarded the 2008 Waller Education Award from the American Statistical Association for innovation in the instruction of elementary statistics.

Watch a video of my talk at TEDxSwarthmore.

Requesting a letter of recommendation from me? Please read this page first.




Biographical info


Positions held
Associate Professor of Statistics, 2008-; Assistant Professor 2002-2008: Swarthmore College, Department of Mathematics and Statistics, Swarthmore, PA
Blaustein Visiting Associate Professor, 2009-2010: Stanford University, Department of Geological and Environmental Sciences, Palo Alto, CA
Lecturer, 1999-2002: Harvard University, Department of Statistics, Cambridge, MA
Visiting Assistant Professor, 1998-1999: Williams College, Department of Mathematics, Williamstown, MA
Instructor, 1996-1998: The University of Chicago, Department of Statistics, Chicago, IL
Programmer, 1992: Data Desk statistical software, Data Description, Inc., Ithaca, NY

Education
PhD, 1998; MS 1994: The University of Chicago, Department of Statistics, Chicago, IL
BS, 1992: Cornell University, Statistics and Biometry, Ithaca, NY

Trivia: What do Stanford, Swarthmore, Harvard, Chicago, and Cornell have in common? (Hint: think team nicknames.)

Personal
I participated in academic quiz competitions while I was a student at Cornell and Chicago. I captained the University of Chicago College Bowl team, the NAQT 1997 International Champions. I also played for the winning team (a three-man Cornell team) at the first ever Questions on the Crum tournament at Swarthmore in 1992.

I was a contestant on Jeopardy! in 1996. I was an alternate on Who Wants to be a Millionaire in 1999 but didn't appear on the show. I did get to meet Regis and John Carpenter (the first million-dollar winner, who was on my taping). Look for me in the audience!

One of my hobbies is songwriting. Some musicians/composers I've been listening to are Steve Reich, The Corrs, October Project, Shiny Toy Guns, Joe Jackson, Chuck Mangione, John Adams, and Aaron Copland. Here is a piece I did for piano and mallet percussion, a piece for rock band, harp, and cello inspired by Copland, and a piece inspired by the 2012 Newtown school shootings.
New: I interviewed Sharon Corr:   Part 1   Part 2




Contact info


Fall 2013 Office Hours
Tuesdays and Wednesdays, 3:30-5:00
or by appointment, or just drop in any time my door is open
Science Center 159

Internet
s c w a n g [at] s w a r t h m o r e [dot] e d u 
http://www.swarthmore.edu/NatSci/swang1

Mailing address
Department of Mathematics and Statistics
Swarthmore College
500 College Ave
Swarthmore, PA, 19081

Phone
voice: (610) 690-5769
fax: (610) 690-6854




Last update: March 20, 2014