Job Market Paper #1 [PDF] (REVISED 12/23)
Perception is Relative: Sequential Contrasts in the Field
A large psychological literature suggests that individuals rely on comparative perception when
making sequential decisions or assessments. Such a perceptual bias could influence behavior in
settings from employee hiring and medical diagnosis to investment appraisal and product evaluation.
This study presents a simple theoretical framework which offers predictions to differentiate
perceptual errors from rational behavior, and provides empirical evidence for such contrast effects.
The empirical focus is an analysis of sequential exam evaluation in a large undergraduate course with
supporting evidence for perceptual errors in speed dating decisions, as well as in sentencing decisions
by judges in PA courts. There is modest evidence that graders are negatively biased when evaluating
exams which follow high and low streaks of extreme exams. Relative to a typical score, this effect is
on the order of a 12% increase in leniency following a streak of three low scoring exams, and a 6%
grade reduction following three high scoring exams. Ostensibly, learning or quotas for high and low
grades could rationally account for this finding. However, the fact that these effects: (i) decay fully
after a single period, (ii) persist despite grader experience, and (iii) are non-existent for highly
transparent (multiple-choice) questions suggests an alternative explanation. Stronger evidence exists
for contrast effects in dating where highly attractive or unattractive prior partners produce a 13 to
17% distortion relative to the baseline decision to date. In judicial sentencing, on days with heavy
caseloads, judges are 8% more likely to be lenient in summary trials after exposure to a criminal
infraction. An original survey of real estate agents suggests that these effects may extend to nonrandom
settings such as home purchases.
Job Market Paper #2 [PDF]
Driving Under the (Cellular) Influence (with Vikram Pathania)
The link between driver cell phone use and crash risk has become an area of active research. Most
existing studies associate cell phone use with substantial crash risk and even compare the danger of
such use to illicit levels of alcohol. We investigate the causal link between cellular usage and crash
rates by exploiting a natural experimentthe discontinuity in marginal pricing at 9pm on weekdays
when recent cell phone plans transition from peak to off-peak pricing. We first document a jump
in call volume of about 20 to 30% at pricing thresholds for two samples of callers. We then document
the corresponding change in the fatal and non-fatal crash rate. Using the years prior to the
introduction of two-tier pricing as a control, as well as weekends as a second control, we find no
evidence for a relative rise in crashes after 9pm on weekdays from 2002-2005. The upper bound of
our estimates rules out increases in all crashes larger than 1.0% and increases larger than 1.3% for
fatal crasheslower than the increase implied by most existing studies. We confirm our results with
three additional empirical approaches: (i) we compare regional trends in cell phone ownership and
crashes, (ii) we estimate the impact of existing legislation banning driver cell phone use, and (iii) we
examine differences in urban and rural crash rates. None of these analyses suggest a link between
cellular use and vehicle crashes. We discuss possible explanations and present a behavioral model to
reconcile this counterintuitive finding with existing research.
Other Papers
Romantic Relativity: Contrast Effects in Speed Dating (with Ray Fisman, in preparation)
Law and Order: Contrast Effects in Judicial Decisions (with Andrea Cann, in preparation)
The Drudge Effect: The Effect of Matt Drudge on Major Media (in preparation)