Provider Unit Cost Trend Engine

python
# Provider Unit Cost Trending
def calculate_unit_cost_trend(current_claims, prior_claims, procedure_code):
    # Pure Unit Cost Trend (same service, different price)
    current_cost_per_service = (
        current_claims[procedure_code].total_allowed / 
        current_claims[procedure_code].service_count
    )
    prior_cost_per_service = (
        prior_claims[procedure_code].total_allowed / 
        prior_claims[procedure_code].service_count
    )
    
    unit_cost_trend = (current_cost_per_service / prior_cost_per_service) - 1
    
    # Utilization Trend (same price, different volume)
    current_services_pmpm = (
        current_claims[procedure_code].service_count / 
        current_claims.total_member_months
    )
    prior_services_pmpm = (
        prior_claims[procedure_code].service_count / 
        prior_claims.total_member_months
    )
    
    utilization_trend = (current_services_pmpm / prior_services_pmpm) - 1
    
    # Total Trend (Multiplicative)
    total_trend = ((1 + unit_cost_trend) * (1 + utilization_trend)) - 1
    
    # Medicare Benchmark Comparison
    medicare_rate = get_medicare_rate(procedure_code, region='national')
    commercial_rate = current_cost_per_service
    medicare_pct = (commercial_rate / medicare_rate) * 100
    
    return {
        'procedure_code': procedure_code,
        'unit_cost_trend': unit_cost_trend,
        'utilization_trend': utilization_trend,
        'total_trend': total_trend,
        'current_unit_cost': current_cost_per_service,
        'medicare_benchmark': medicare_rate,
        'medicare_pct': medicare_pct,
        'attribution': {
            'unit_cost_contribution': unit_cost_trend / total_trend * 100,
            'utilization_contribution': utilization_trend / total_trend * 100
        }
    }

# Example Output for CPT 70553 (MRI Brain w/ and w/o Contrast):
# {
#   'unit_cost_trend': 0.092,  # +9.2% unit cost inflation
#   'utilization_trend': 0.035,  # +3.5% utilization growth
#   'total_trend': 0.129,  # +12.9% total
#   'current_unit_cost': 1250,
#   'medicare_benchmark': 438,
#   'medicare_pct': 285,  # Paying 2.85x Medicare
#   'attribution': {
#       'unit_cost_contribution': 71%,  # Price is the problem
#       'utilization_contribution': 27%   # Volume is secondary
#   }
# }