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Forecasts

Method

Forecasts use recent-slope extrapolation based on the last 2 data points, projecting 5 years forward.

Two forecast charts are displayed on the homepage:

Affordability forecast

  • Shows housing affordability index over time
  • Solid line = historical data, dashed line = projection
  • Y-axis: index (base year = 100)

Rent burden forecast

  • Shows what percentage of net salary rent costs
  • Solid line = historical data, dashed line = projection
  • Y-axis: % of net salary

Implementation

src/compute/forecast.rs contains:

  • linear_regression() – full dataset regression (kept but unused)
  • recent_slope() – slope from last 2 data points
  • extrapolate_recent() – project values forward
  • build_affordability_forecast() – Chart.js-ready data
  • build_rent_burden_forecast() – Chart.js-ready data

Chart rendering

Forecast data is served as JSON from /api/chart/forecast and /api/chart/rent-burden, rendered client-side by loadForecastChart() in charts.js.