1. Gentrification
● Production side ● Consumption side
explanations explanations
– Rent-gap theory (N.Smith, – Post-industrial shift
1979) G. depends on the ● Predominance of white collar
movement of capital from one work
area of the city to the other in
pursuit of higher profit
● 'Creative' classes
Urban development, technological shift,
● Fashion effects (NY 'loft
depreciation create localized mismatch living')
between current and potential land use

2. This model
● So far...
– Implements the rent-gap theory
● Wishes to
– Couple economic and cultural/diversity dynamics.
● Gentrification affects the cultural other than economical
identity of places.
– Embed + compare production and consumption
factors → “theoretical synthesis”
– Predict the future! :-)

3. Agent model
➔ Income level [0-1] (random)
➔ Mobility propensity (Poisson distribution 0.06/year)
➔ String culture (n=10) |_|_|_|_|_|_|_|_|_|_|
0100101011 1011011001
0
1
0
0
0
0
1
0
1
0
● Long-time neighbours interact → Cultures mix
● Interaction more likely when common traits exist

4. City model
● Individual dwelling
– Condition [0-1] random
– Price [0-1] = cond + 0.15
● Neighbourhood
– Allure (sticky and approximate)
|_|_|_|_|_|_|_|_|_|_|
Price-gap:
difference between a property's price and
mean price of surrounding properties

5. Parameters
● Kapital level
– Number of properties receiving investment each
year
● Decay factor
– Constant monthly decay. Set at 0.0015
● Immigration rate
– Set at 3% per year

6. Economic processes
● Decay
– Constant decay (0.0015/step)
– Empty properties decay 1.5x faster
– Price is lowered as consequence of decay and if
empty for 6 consecutive months
● Investment
– K properties with wider price-gap receive investment
● Price = mean neighbour's price + 15%
● Condition = 0.95

7. Residential choice process

8. Decision to move
● Dissonance ● Poor dwellings
– “Spatial cognitive – Prolonged stay in
dissonance” when “slum” increases
neighbours too mobility propensity
different ● Price increase
– High dissonance
increases mobility
– Price increase puts
propensity the agent in 'seek-
new-place' mode

9. Results

10. Spatial dynamics
K=10 (2.2%) K=15 (3.5%) K=20 (4.5%)
K=25 (5.6%) K=30 (6.8%) K=35 (8%)

11. Population dynamics
K=15
Gini = 47; Slum 62%

12. K=25
Population dynamics
Neighbourhoods
steadily increasing
the mean income,
while the population
decreases and
increases in waves,
signal gentrification +
displacement: the
poor go, the rich
Gini = 40; move in.
Slum = 30%

13. K=25
Cultural dynamics
➔ Cultural uniformity is
maximized in areas where
prices have been stable for a
long time at a high level
➔ Little clustering happens in
poor areas: the "slum" is a
transition zone for poor
immigrants, who quickly enter
and leave.

14. Population dynamics
K=35
➔ Higher capital = higher prices = lower population
➔ Cycles of investment and disinvestment
➔ Rat race around the city
➔ Reminds of Smith's definition

15. Cultural dynamics
Culture uniforms when
prices are steady for
some time, allowing for
➔ residents to stay put
➔ cultures mix
➔ self-selection of in-
movers via “allure”

16. Future
● More realistic residential mobility
● More heterogeneous agents
– Classes of agents: “gentrifiers” and “non-
gentrifiers”
● Population dynamics
● Actual city land values