2025-12-07

Overview

Today we’ll explore:

  • How education affects life expectancy
  • How income affects life expectancy
  • What happens when we look at both together
  • Statistical evidence for these relationships

Research Question


Do countries with higher average years of schooling and higher income levels have significantly greater life expectancy?

Data Source

World Health Organization (WHO) Life Expectancy Dataset

  • Dataset: Life Expectancy (WHO) on Kaggle

  • Countries: ~190 countries worldwide

  • Time period: 2000-2015

  • Key variables:

    • Life Expectancy (years)
    • Schooling (average years)
    • Income composition of resources
    • Health indicators, mortality rates, diseases

Study type: Observational (we observe patterns, not experiments)

Part 1: Does Education Matter?

Let’s look at the relationship between years of schooling and life expectancy

Education & Life Expectancy

Pattern: Clear upward trend—more education = longer life

Testing the Education Effect

Statistical Test Results:
Group Average Life Expectancy
High Schooling 75.5 years
Low Schooling 62.9 years
Difference 12.6 years
P-Value 0


P-value: < 0.001 (Highly significant!)

What this means: Countries with more education have 12.6 years longer life expectancy on average. This is definitely real, not random chance.

Part 2: Does Income Matter?

Let’s compare life expectancy across three income groups

Life Expectancy by Income Group

Pattern: Clear upward steps from Low → Medium → High income

Distribution Shapes

Key insight: High-income countries are consistently high; low-income countries vary widely

Precise Estimates with Confidence Intervals

Gap between Low and High: ~17.6 years!

Statistical Confirmation (ANOVA)

ANOVA Test Results:


  • F-statistic: 1132.3 (very high = big differences between groups)
  • P-value: < 0.001 (extremely significant)


What this means: The differences between income groups are definitely real and substantial. Income level matters enormously for life expectancy.

Summary: Income Groups

Income Group Average (years) Lower 95% CI Upper 95% CI
Low 57.9 56.9 58.9
Medium 65.0 64.6 65.4
High 75.5 75.1 75.8

Bottom line: A 17.6-year gap between Low and High income countries

Part 3: Combined Effects

What happens when we look at BOTH education AND income together?

Four Categories of Countries

We created four groups:

  1. High Schooling & High Income - Both advantages
  2. High Schooling & Low Income - Education but limited resources
  3. Low Schooling & High Income - Resources but less education investment
  4. Low Schooling & Low Income - Double challenge

Combined Effects Visualization

Key finding: Countries with BOTH advantages (upper right) achieve 75-85 years

Distribution Across Categories

Top Performers by Category

Top Performers: Countries with the Longest Life in Each Category
category countries
High Schooling & High Income Japan, Sweden, Iceland
High Schooling & Low Income Lebanon, The former Yugoslav republic of Macedonia, Saint Vincent and the Grenadines
Low Schooling & High Income Mexico, Albania, Oman
Low Schooling & Low Income Bosnia and Herzegovina, Maldives, Antigua and Barbuda

Insight: Even within similar circumstances, some countries excel—what are they doing right?

Key Findings: Summary

1. Education Effect - Countries with high schooling: 75.5 years - Countries with low schooling: 62.9 years - Difference: ~12.6 years (p < 0.001)

2. Income Effect - Low income: ~57.9 years - High income: ~75.5 years - Difference: ~17.6 years (p < 0.001)

3. Combined Effect - Having BOTH advantages = 75-85 years (best outcomes) - Having NEITHER = 50-65 years (toughest challenges)

Statistical Confidence

All our tests showed extremely strong evidence (p < 0.001):

  • Less than 0.1% chance these patterns are random
  • The relationships are real and substantial
  • Results would replicate with different data samples

Translation: We can be very confident that education and income genuinely matter for life expectancy.

What This Means

For Understanding the World: - Explains why life expectancy varies so much globally - Shows that human development indicators (education, income) are key

For Policy: - Investing in education is linked to longer lives - Economic development is linked to better health outcomes - Working on both together may be most effective

The Hopeful Part: - Progress is possible—countries at all levels show examples of success - Smart policies can make a difference even with limited resources

Important Limitations

What we CAN’T say: - We can’t prove education or income directly cause longer life - This is observational data, not an experiment

Other factors matter too: - Healthcare quality - Clean water and sanitation - Political stability - Environmental conditions - Cultural practices

Country averages hide variation: - Inequality within countries matters - Some people do much better/worse than the average

Conclusions

Main Answer: YES

Countries with higher education and higher income have significantly greater life expectancy.


The evidence is strong, consistent, and meaningful.


Both education and income matter independently, but having both creates the best outcomes—representing a difference of 10-20+ years of life.