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Round Numbers as Goals: Evidence from Baseball, SAT & ‘the Lab’. (with Devin Pope, In press, Psychologial Science). The Paper in one slide. Rosch ( Cog Psych 1975): ‘Cognitive Reference Points’ Focal values in categories used to judge other values Our question: in a JDM way?
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Round Numbers as Goals:Evidence from Baseball, SAT & ‘the Lab’ (with Devin Pope, In press, Psychologial Science)
The Paper in one slide • Rosch (Cog Psych 1975): ‘Cognitive Reference Points’ • Focal values in categories used to judge other values • Our question: in a JDM way? • Focus on performance scales • Prediction: P1: more effort just below RN P2: more f() just above RN Findings: • Baseball: • ‘Too many’ batters with a .300 batting average • SAT: • ‘Too many’ retake with __90 vs. __00 • Lab: • More likely to keep trying _9 vs. _0 8 7.7
Study 1: Baseball Background • Balls are thrown • Batters take turns (“at-bats”) • If ball is hit ~ >“hit” • Batting average: “hits” / “at-bats” • BA is a good DV because: • Granular • Paid attention to by players • BA ~ {.200-.400}
Study 1: Baseball (2) • Sole ‘round’ number: .300 • Hypothesis: batters disproportionately prefer .300 to .299 • Predictions: 1) ‘too many’ .300 season averages 2) Try hard to get/keep .300
Data • All player-seasons 1975-2008 • N=11,430 • Granularity: > 200 at-bats • N=8,817 • Graphs will focus on those with .280-.320 • N=3,083
Graph: Batting Averages(raw freqs) At the end of the season With 5 plate-appearences left Z = 7.35, p<.001
How do batters achieve that? • Next, look at last play of season. • Hits • Walks • Substitutions
Do .299 hit more on their last at-bat? Endogenous exit for sure. Better actual performance, maybe.
Summary Study 1 • “too many” .300 season averages • Achieved by • Fewer walks at .299 • Substitutions at .300 • Maybe: greater hitting %.
Limitations • One round number got lucky? • It is a small effect • Not in p-value • Not in SD • In terms of consequences • (just one play in the season) • Agents, managers, advertisers?
Study 2: SAT re-taking • Many round numbers • Stakes are larger • Third party problem remains • But addressed empirically • Also: see Study 3
Background on the SAT • Scored 400-1600 • Intervals of 10 • Retaking is allowed • (about 50% do) • HS Juniors and Seniors take it • Prediction: “too many” retake it if __90 vs __00
Data • College Board Test Takers Database • N= 4.3 million; 1994-2001 • Last test only • Did individual retake it? • D/K! • Infer retaking rates from score distributions
Inferring Retaking Rates • Don’t observe key DV • But: • Juniors can easily retake • Much more difficult for seniors • Juniors (but not seniors) should have • “too few” __70,__80,__90 scores • “too many” __00, __10 __20
Let’s see Graph with raw frequencies next
A better graph Plotting the slope F(x)/F(x-10) (Uri: Explain Ratio=1)
Graph with F(x)/F(x-10) Explain the effect is not ONLY at __90
Interpretation and Alternative Explanations • Find: big jumps in F(x) at _00 (for juniors) • Infer: disproportionate retaking below _00 • Interpret: _00 is a goal • BUT 1) Maybe _00 really is discontinuously better • Version 1. Same effect, different agent • (can live with) • Version 2. Arbitrary thresholds • (less so) 2) Maybe _00 is perceived as discontinuously better by test-taker Next, look at (1) & (2) empirically.
1) Is it discontinuously better to get a _00 than _90 in the SAT? • Compare admission with _90 and _00 • Data 1:(JBDM 2007) “Clouds Make Nerds Look Good” • N=1100 undergrad admission decisions • Null: pr(admit|SAT=1000) -pr(admit|SAT=990)= pr(admit|SAT=1010)-pr(admit|SAT=1000) • Tested at: • 1200, p=.96 • 1300, p=.99 • 1400, p=.20 • 1500, p=.92 • Small N, but nothing there directionally. • SAT not that important.
Same test, different dataset • Data 2: ‘Ongoing’ project with Francesca Gino • MBA admission decisions & GMAT (<800) • GMAT=600, p=.09 (wrong sign) • GMAT=700, p=.93
Alternative Explanations 1) Maybe _00 really is discontinuously better 2) Maybe _00 is perceived as discontinuously better by test-taker
Back to SAT dataset • Score sending reveals info. • If _00 disc. better than _90 scores sent to disc. different schools. • Next: the graph • Schools predicted by score
Summary • Too many _70,__80,__90 retake SAT • About 10%-20% percentage-points too many • No effect on admission decisions • No effect on score sending decisions • We interpret: • _00 (becomes) a goal influencing retake decision if met/not-met.
Motivation of Study 3 • Studies 1 & 2 show large effects in the field • Alternative explanation: third party • Keep in mind though, that: • Baseball managers think locus is players • Also, here 3rd party locus is interesting. • Does not predict admissions • Does not predict where SATs are sent • Study 3, eliminate by design
Study 3 • Scenarios inspired by Heath Larrick and Wu (Cog Psyc1999) • “Imagine your performance is x” • “how motivated to do more”? 1-7 • X is • below round number • just belowround number • above round number.
Scenario 1 Imagine that in an attempt to get back in shape, you decide to start runninglaps at a local track. After running for about half an hour and having done [18/19/20 ; 28/29/30] laps you start feeling quite tiredand are thinking that you might have had enough. How likely do you think it is that you would run one more lap?