base rate:
Only 1 of 8 post-1991 Colombian presidential elections (Uribe 2002) produced a first-round winner, giving ~12.5% base rate. Colombian political fragmentation typically produces runoffs.
evidence updates:
Latest April 2026 Invamer poll shows leader Cepeda at 44.3%, ~6 points below threshold. This pushes probability DOWN from 12.5% base rate by ~5% because the leader is meaningfully short and time is limited (election in May/June 2026). Three-way fragmentation with viable second/third candidates further reduces consolidation potential. Petro's polarized approval (49/49) caps Cepeda's ceiling.
combination method:
The first-round win requires the leader to actually exceed 50% of valid votes. Given Cepeda's 44.3% polling and structural fragmentation, and adjusting historical base rate downward given specific evidence, I estimate ~8%.
final:
Strong evidence points to a runoff. Probability of first-round winner: ~8%.
ensemble:
{'ensemble_count': 3, 'perspectives': {'base_rate': {'p_yes': 0.08, 'confidence': 0.75}, 'evidence_driven': {'p_yes': 0.05, 'confidence': 0.85}, 'contrarian': {'p_yes': 0.06, 'confidence': 0.82}}, 'spread': 0.03, 'individual_p_yes': {'base_rate': 0.08, 'evidence_driven': 0.05, 'contrarian': 0.06}}