Urban Planning Methods and Techniques
This domain tests method selection and small quantitative reasoning: projection, sampling, weighting and evaluation. You will rarely be asked for heavy mathematics - you will be asked whether a method is appropriate.
Core toolkit
- Population projection - geometric/exponential for short horizons, cohort-component for age structure, logistic where saturation is plausible, ratio and employment-led methods for local forecasts.
- Survey design - sampling frame, stratified or cluster sampling, sample size from margin of error; land-use inventory by parcel.
- Threshold analysis - identify the point at which a constraint (slope, water, infrastructure capacity) makes development infeasible.
- Structured judgement - Delphi, SWOT, scenario planning; multi-criteria evaluation - AHP (Saaty) with consistency ratio, weighted overlay.
- Evaluation - cost-benefit, cost-effectiveness, distributional (who gains?) analysis.
Worked example
A city of 100,000 grows at 2% per year. Geometric projection: 100,000 × 1.02¹⁰ ≈ 121,900. If you instead add 2,000 people per year arithmetically you get 120,000 - close here, but the geometric result diverges sharply over 30 years, and the arithmetic method is indefensible when the growth rate is itself falling. Reasoning to write down: state the method, state the assumption about constant rate, then test sensitivity with a lower rate, because Iranian fertility has fallen steeply and constant-rate extrapolation over decades is the standard error.
Traps
- Using arithmetic growth for long horizons.
- Presenting AHP weights as objective truth; they are structured judgements and need a consistency check.
- Forgetting that a land-use survey must record parcel-level attributes, not only aggregate areas.