Scales of Analysis - Quick Reference

Global Scale

• Purpose: compare across countries; understand patterns at the macro level.
• Example: Share of population in extreme poverty, 2017. Extreme poverty = per capita household consumption below $1.90$ international dollars per day (in $2011$ PPP prices).
• Data context: international dollars adjusted for inflation and cross-country price differences; sources include Our World in Data and the World Bank.

Regional Scale

• Purpose: compare regions or groups of countries; reveal regional variations.
• Example (regional focus in Africa): African countries with the largest forcibly displaced populations (FDP):
  • SUDAN: $2{,}864{,}228$ FDP
  • ERITREA: $585{,}874$ FDP
  • ETHIOPIA: $2{,}362{,}517$ FDP
  • NIGERIA: $2{,}272{,}661$ FDP
  • CAMEROON: $847{,}196$ FDP
  • DRC: $3{,}937{,}043$ FDP
  • SOMALIA: $3{,}514{,}151$ FDP
  • SOUTH SUDAN: $4{,}144{,}430$ FDP
  • BURUNDI: $449{,}196$ FDP
• Data sources: UNHCR, IDMC, UN DESA.
• Purpose: illustrate how regional context shapes displacement and indicators.

National Scale

• Purpose: analyze at the country level; facilitates comparisons across entire nations.
• Example: United States and Puerto Rico poverty patterns (2018). Source: U.S. Census Bureau, ACS 1-Year Estimates & 2018 Puerto Rico Community Survey.
• Note: U.S. nationwide poverty rate reported as $13.1\%$ (Puerto Rico data excluded).

Sub-State / State Level

• Purpose: analyze within-country divisions (states or equivalent subdivisions).
• Example: State-level or substate maps illustrating poverty or other indicators across states (e.g., U.S. states and territories).

County Level

• Purpose: analyze at the county level to show more granular spatial variation.
• Example: County Poverty Rate for the United States (2013–2017). Source: American Community Survey 5-Year Estimates.
• Map displays: counties color-coded by poverty rate categories (e.g., 30.0% or more; 20.0–29.9%; etc.).

City / Local Scale

• Purpose: fine-grained view of neighborhoods and urban areas.
• Example: Local-scale maps highlight neighborhood-level patterns not visible at broader scales.

Census Tract

• Definition: smallest standard scale of analysis; typically comprises about $1{,}000{-}8{,}000$ people.
• Relevance: closest to the size of an actual neighborhood; used for high-resolution local analysis.

Zooming In & Zooming Out

• Small scale maps: show LARGE area with SMALL amounts of data; big numbers on the map; zoomed OUT.
• Large scale maps: show SMALL area with LARGE amounts of data; small numbers on the map; zoomed IN.
• Concept: scales are used to tell a story by controlling data density and geographic extent.

Patterns, Processes, and Interpretations Across Scales

• Different scales reveal variations in spatial patterns.
• Patterns and processes at different scales lead to variations in, and different interpretations of, data.
• Implication: choose the scale that matches the question and the interpretation needs.

Health & Demographics Illustrations by Scale

• Example: Ethiopia and sub-Saharan Africa maternal mortality trends (regional health indicators).
• Purpose: demonstrate how health metrics can vary across scales and regions.