Research basis & scenario method
This project examines spatial changes in Frankfurt's officially published land reference values (Bodenrichtwerte) for 2022, 2024 and 2026.
The spatial approach — using BORIS value zones as the unit of analysis — is informed by Siedentop & Schartmann (2025), who study urban land-value change in North Rhine-Westphalia with official BORIS data. Research on statistical land valuation (Kolbe et al., 2019) and on urban land price dynamics (Fitzgerald et al., 2020) gives context for valuation methods and for why land prices are volatile and should not be extrapolated with confidence.
Future values for 2028, 2030 and 2035 are exploratory scenarios, not forecasts: BRWyear = BRW2026 × (1 + r)year − 2026, with r = 0 (M1), ½ × CAGR22–26 (M2), CAGR22–26 (M3) or a user rate (M4). M2 and M3 are only computed where a 2022 value could be matched. None of the cited studies validates these coefficients; they are transparent assumptions.
Simulation. 1,000 Monte Carlo runs per zone. Yearly growth = μ + δ + σ·(0.5 zyear + 0.7 εzone,year), where μ blends the zone's own CAGR with the median of its land-use group (½ / ½), δ ~ N(0, 2.5 %/yr) is a persistent trend uncertainty per run and group, and σ is the robust spread of zone CAGRs in the group. The map shows the P10, P50 or P90 value; the fan chart the median zone of a group.
Heat what-if. Zones are split into thirds by mean summer land-surface temperature (Landsat 8/9, clear days June–August 2022–2025). The slider adds or removes growth in the hottest third. It is a sensitivity test, not evidence that heat moves land values.
Data quality & limits
A Bodenrichtwert is an official reference value for land in a zone under stated conditions (use, development state, floor-area ratio). It is not a transaction price and not the value of a single plot.
2022 and 2024 values are matched to the 2026 zones by zone number and land-use code. The 2022/2024 sources are attribute tables; whether zone boundaries stayed the same is not verified, so changes of individual zones should be read with care.
Land-surface temperature describes how hot surfaces get around 10:30 on clear summer days, not air temperature.