How to Simulate Geo Experiments in Python

import random
import math
from dataclasses import dataclass

@dataclass
class GeoMarket:
    name: str
    base_demand: float
    geo_coefficient: float

def simulate_geo_experiment(markets, weeks=12, control_weeks=6):
    """
    Simulates a geo experiment with ramp-up and ramp-down periods.
    Returns weekly lift percentages for treatment vs control.
    """
    results = []
    for week in range(1, weeks + 1):
        # Ramp factor: 0% for control weeks, ramps up to 100% then down
        ramp = 0.0
        if week > control_weeks:
            elapsed = week - control_weeks
            total_treatment_weeks = weeks - control_weeks
            ramp = math.sin(math.pi * (elapsed - 0.5) / total_treatment_weeks) * 0.5 + 0.5
            ramp = max(0.0, min(1.0, ramp))

        treatment_total = 0.0
        control_total = 0.0
        for market in markets:
            noise = random.gauss(0, 1)
            weekly_demand = market.base_demand * (1 + market.geo_coefficient * noise)
            if ramp > 0 and market.name.startswith("T"):
                weekly_demand *= (1 + 0.15 * ramp)  # 15% max lift
            if market.name.startswith("C"):
                control_total += weekly_demand
            else:
                treatment_total += weekly_demand

        if control_total > 0:
            lift = (treatment_total / control_total - 1) * 100
            results.append((week, round(lift, 2), round(ramp, 2)))
        else:
            results.append((week, 0.0, round(ramp, 2)))

    return results

def main():
    random.seed(42)
    markets = [
        GeoMarket("C-NY", 1000, 0.2),
        GeoMarket("C-CA", 800, 0.15),
        GeoMarket("T-TX", 900, 0.18),
        GeoMarket("T-FL", 700, 0.12),
    ]
    print("Geo Experiment Mock Markets")
    print("Week | Lift % | Ramp %")
    for week, lift, ramp in simulate_geo_experiment(markets):
        print(f"{week:4d} | {lift:6.2f} | {ramp*100:5.1f}%")

if __name__ == "__main__":
    main()