IB Geography 1.1.4 Synthesis, Evaluation and Skills Opportunities Notes

Relative Importance Is a Judgment, and the Judgment Rests on Scale

1. A list of factors is knowledge.
2. A ranked and evidenced argument about which factor matters most is evaluation.
3. Development level belongs in the ranking as well, because a country's income group decides how much capital is available to overcome a physical limit.

The Ranking of Influences Shifts as the Scale Shifts

1. At the global scale
   1. Climate, water and relief set the outer envelope within which dense settlement is possible.
   2. Arid and polar interiors hold very few people for the area they cover, so physical factors do most of the explaining at this scale.
   3. Even here the envelope is not fixed, since Cairo, Dubai and Phoenix all sit in arid land that investment has made habitable.
2. At the national scale
   1. Much more of a country's territory is habitable than is densely settled, so the physical envelope explains less.
   2. Economic opportunity, infrastructure and government policy decide which habitable places fill up.
   3. Income group matters at this scale, because piping water to a dry region is a choice a high-income state can fund and a low-income one often cannot.
3. At the local scale
   1. Land price, transport access and planning rules decide who lives on which street.
   2. Physical factors return in a narrow form, such as flood risk pushing housing off a floodplain.
4. The same question therefore has three defensible answers.
5. An answer has to name the scale it is judging at.

Places Explain Each Other Through the Flows Between Them

1. A core and its periphery are one system, linked by flows that run in opposite directions.
   1. People move toward the core.
   2. Earnings move back to the periphery.
   3. The core gains working-age adults, so the periphery is left with an older age structure it did not choose.
2. A city's population is therefore partly an account of other places.
   1. Shenzhen drew migrants from inland provinces, though its growth also came from natural increase and from boundary changes.
3. Interaction crosses borders, since a port city's size depends on markets on other continents.
4. The same logic works locally, because one suburb's growth is often a nearby district's decline.
5. The strength of an interaction is not fixed, because falling transport and communication costs let flows reach further than before.

A Strong Answer Ranks, Evidences, Then Resolves

1. State the judgment first, naming the influence and the scale.
   1. For instance: at the national scale in South Africa, political history outweighs physical geography.
2. Evidence it with a named place, a figure and the mechanism that joins them.
   1. Gauteng is the smallest province by area and holds about 16 million people, because the goldfields drew workers and apartheid law then fixed where they could live.
3. Put the strongest case against your judgment, using a place where the ranking comes out the other way.
   1. Egypt serves here, since the Nile corridor is the only well-watered ground and no policy has changed that.
4. Close by resolving the tension rather than restating both sides.
   1. A resolution usually turns on scale, on timeframe, or on which group of people is being asked about.

The Technique You Choose Decides What the Reader Can See

1. Assessment objective 4 covers the selection, use and application of appropriate skills and techniques.
2. Choropleth map
   1. Use it for a rate or a density across areas, such as population density by country or province.
   2. Its weakness is that each area is shown as internally uniform, so variation inside a unit disappears.
   3. Large units also dominate the map visually however few people they hold, and the class boundaries are the cartographer's choice.
3. Proportional symbol map
   1. Use it for totals at points, such as the population of each megacity.
4. Flow-line map
   1. Use it for movement between places, such as internal migration toward the coast.
5. Lorenz curve and Gini coefficient
   1. Use them to show how unevenly something is shared, such as income within a country.
6. Scatter graph
   1. When 2025 values for GDP per capita and urban population share are plotted on a scatter graph, they show a positive association. The wide scatter means the graph cannot show that income alone causes urbanization.

Naming and Reading the Result

1. Use the technical name, because "choropleth map" earns credit where "colored map" does not.
2. Interpret the result geographically, naming the places the pattern picks out rather than describing the shape of the line.