Senior Project Presentations

Time MattersTime Matters

• Presentation Time Limit -- 7 minutes – Going over will effect your grade!– Not counting questions

• Determine What Points Are Worth Making

(Do This Before Making PP Slides)

Overview of Slide Types

• Defining the Topic/Problem– Build interest in economic content

• Background

• Key Findings

• Questions/Problems/Issues

From Written Report to PowerPoint

• How Many Slides?– @ x minutes per slide

• Remember, slides should augment, not replace, oral presentation: – Emphasis – Illustration (tables/graphs)– Clarification

Example: “Positional Segregation”

Positional Segregation in Sports

Discrimination or Comparative Advantage

Positional Segregation: The Issue

• NFL in late 1990s: white-black QB ratio 3:1 while cornerback ratio 1:60

• MLB in 1980s: blacks comprise 7% of pitchers but 70% of outfielders

• Does figures such as these reflect discrimination or some underlying competitive advantage?

Possible Economic Explanations

• Employer-Manager, Employee, or Fan bias (Scully 1974; Curtis and Loy 1978; Yetman 1987)

• Different Training opportunities (Medoff 1986)

• Non-discrimination Explanations?– Differences in Underlying Athletic Abilities

“Athletic Endowment”

Distribution of Athletic Endowments

• At Individual Level – prima facie evidence

• At Aggregate Levels Marked by Geographic Areas or racial/ethnic Groups?– Anecdote/Science of Nepalese Sherpas– Mixed Evidence from Exercise Science– Related Evidence in Medical Problems

Key Caveats

• Not assuming a correlation between athletic skill and mental capacity.

• Not limited to race-based groupings -- broader and narrower than race alone

Evidence

• Does Track & Field Performance Differ by Ancestral Region?– Data for top 20 performing athletes in variety of

events– Contingency Table Analysis

• Comparisons of Regional Percentages

– Logistic Regression• Controlling for differences in population and income

Contingency Table

________________________________________________________________________

Sprints Middle Distance Long Distance Strength________________________________________________________________________

East Africa 3.3 50 67.5 2.5

North Africa/ 0 17.5 20 10Middle East

Spain/Portugal/ 5 10 7.5 2.5Latin, South Am.

Sub-Saharan 88.3 2.5 0 2.5West Africa

Western Europe 1.7 20 5 40

Eastern Europe 1.7 0 0 40

East Asia 0 0 0 2.5

Chi-Square 245p-value (0.0001)

Logistic Regression

Dependent VariableSprints Middle Distance Long Distance Strength

________________________________________________________________________

Constant -2.90 -2.24 -2.85 1.28(0.30) (0.01) (0.01) (0.07)

Per Capita -6.9e-5 1.0e-4 -3.0e-5 -6.8e-5GDP (0.31) (0.01) (0.50) (0.10)

Population 0.002 -0.01 0.01 0.01(0.82) (0.01) (0.61) (0.02)

East Africa -0.20 2.10 3.00 -12.73(0.88) (0.01) (<0.01) (0.74)

North Africa/ 1.51 1.36 2.54 -3.84Mediterranean (0.21) (0.05) (0.01) (<0.01)

Sub-Saharan 7.69 -1.96 -7.23 -5.92West Africa (<0.01) (0.09) (0.74) (<0.01)

Asia -4.85 -5.62 -7.21 1.28(0.02) (0.72) (0.92) (0.07)

Chi-Square 164 46 70 123(p-value) (<0.01) (<0.01) (<0.01) (<0.01)% Correct 95.0 73.3 79.4 92.2Psuedo-R2 0.83 0.35 0.49 0.76________________________________________________________________________

Evaluating Results

• What is the basis of this geographic dependence? – Managerial/Employee/Customer Bias?– Training?– Comparative Advantage?

• How Big of a Difference Might Comparative Advantage Make?– Small differences & distributional effects, see

Martel, et al, American Psychologist (1996)