CWICR Crew Optimizer
Business Case
Problem Statement
Crew planning challenges:
- Right mix of workers?
- Optimal crew size?
- Balance cost vs productivity?
- Match skills to work?
Solution
Optimize crew composition using CWICR labor productivity data to balance cost, output, and skill requirements.
Business Value
- Optimal productivity - Right-sized crews
- Cost efficiency - No overstaffing
- Skill matching - Proper worker mix
- Schedule support - Meet deadlines
Technical Implementation
import pandas as pd
import numpy as np
from typing import Dict, Any, List, Optional, Tuple
from dataclasses import dataclass, field
from enum import Enum
from datetime import date, timedelta
class WorkerType(Enum):
"""Types of workers."""
FOREMAN = "foreman"
JOURNEYMAN = "journeyman"
APPRENTICE = "apprentice"
LABORER = "laborer"
OPERATOR = "operator"
HELPER = "helper"
class Trade(Enum):
"""Construction trades."""
CONCRETE = "concrete"
CARPENTRY = "carpentry"
MASONRY = "masonry"
STEEL = "steel"
ELECTRICAL = "electrical"
PLUMBING = "plumbing"
HVAC = "hvac"
PAINTING = "painting"
ROOFING = "roofing"
GENERAL = "general"
@dataclass
class Worker:
"""Worker definition."""
worker_type: WorkerType
trade: Trade
hourly_rate: float
productivity_factor: float = 1.0
overtime_multiplier: float = 1.5
@dataclass
class CrewComposition:
"""Crew composition."""
name: str
trade: Trade
workers: List[Tuple[WorkerType, int]] # (type, count)
base_productivity: float # Output per hour
hourly_cost: float
daily_output: float
@dataclass
class CrewOptimizationResult:
"""Result of crew optimization."""
work_item: str
quantity: float
unit: str
recommended_crew: CrewComposition
alternative_crews: List[CrewComposition]
duration_days: float
total_labor_cost: float
cost_per_unit: float
# Standard crew compositions
STANDARD_CREWS = {
'concrete_small': {
'trade': Trade.CONCRETE,
'workers': [(WorkerType.FOREMAN, 1), (WorkerType.JOURNEYMAN, 2), (WorkerType.LABORER, 2)],
'productivity': 1.0
},
'concrete_large': {
'trade': Trade.CONCRETE,
'workers': [(WorkerType.FOREMAN, 1), (WorkerType.JOURNEYMAN, 4), (WorkerType.LABORER, 4), (WorkerType.OPERATOR, 1)],
'productivity': 1.8
},
'masonry_standard': {
'trade': Trade.MASONRY,
'workers': [(WorkerType.FOREMAN, 1), (WorkerType.JOURNEYMAN, 2), (WorkerType.HELPER, 2)],
'productivity': 1.0
},
'carpentry_framing': {
'trade': Trade.CARPENTRY,
'workers': [(WorkerType.FOREMAN, 1), (WorkerType.JOURNEYMAN, 3), (WorkerType.APPRENTICE, 1)],
'productivity': 1.0
},
'electrical_rough': {
'trade': Trade.ELECTRICAL,
'workers': [(WorkerType.FOREMAN, 1), (WorkerType.JOURNEYMAN, 2), (WorkerType.APPRENTICE, 1)],
'productivity': 1.0
},
'plumbing_rough': {
'trade': Trade.PLUMBING,
'workers': [(WorkerType.FOREMAN, 1), (WorkerType.JOURNEYMAN, 2), (WorkerType.APPRENTICE, 1)],
'productivity': 1.0
}
}
# Default hourly rates by worker type
DEFAULT_RATES = {
WorkerType.FOREMAN: 65,
WorkerType.JOURNEYMAN: 55,
WorkerType.APPRENTICE: 35,
WorkerType.LABORER: 30,
WorkerType.OPERATOR: 60,
WorkerType.HELPER: 28
}
class CWICRCrewOptimizer:
"""Optimize crew composition using CWICR data."""
HOURS_PER_DAY = 8
def __init__(self,
cwicr_data: pd.DataFrame = None,
custom_rates: Dict[WorkerType, float] = None):
self.cost_data = cwicr_data
self.rates = custom_rates or DEFAULT_RATES
if cwicr_data is not None:
self._index_data()
def _index_data(self):
"""Index cost data."""
if 'work_item_code' in self.cost_data.columns:
self._code_index = self.cost_data.set_index('work_item_code')
else:
self._code_index = None
def get_labor_norm(self, code: str) -> Tuple[float, str]:
"""Get labor hours per unit from CWICR."""
if self._code_index is None or code not in self._code_index.index:
return (1.0, 'unit')
item = self._code_index.loc[code]
norm = float(item.get('labor_norm', item.get('labor_hours', 1)) or 1)
unit = str(item.get('unit', 'unit'))
return (norm, unit)
def calculate_crew_cost(self, workers: List[Tuple[WorkerType, int]]) -> float:
"""Calculate hourly cost of crew."""
total = 0
for worker_type, count in workers:
rate = self.rates.get(worker_type, 40)
total += rate * count
return total
def build_crew(self,
name: str,
trade: Trade,
workers: List[Tuple[WorkerType, int]],
base_productivity: float = 1.0) -> CrewComposition:
"""Build crew composition."""
hourly_cost = self.calculate_crew_cost(workers)
daily_output = base_productivity * self.HOURS_PER_DAY
return CrewComposition(
name=name,
trade=trade,
workers=workers,
base_productivity=base_productivity,
hourly_cost=hourly_cost,
daily_output=daily_output
)
def optimize_for_work(self,
work_item_code: str,
quantity: float,
target_days: int = None,
max_crew_size: int = 10) -> CrewOptimizationResult:
"""Optimize crew for specific work item."""
labor_norm, unit = self.get_labor_norm(work_item_code)
total_hours = quantity * labor_norm
# Detect trade from code
trade = self._detect_trade(work_item_code)
# Generate crew options
crews = []
# Small crew
small_workers = [(WorkerType.FOREMAN, 1), (WorkerType.JOURNEYMAN, 2), (WorkerType.LABORER, 1)]
small_crew = self.build_crew("Small Crew", trade, small_workers, 1.0)
crews.append(small_crew)
# Medium crew
med_workers = [(WorkerType.FOREMAN, 1), (WorkerType.JOURNEYMAN, 3), (WorkerType.LABORER, 2)]
med_crew = self.build_crew("Medium Crew", trade, med_workers, 1.4)
crews.append(med_crew)
# Large crew
large_workers = [(WorkerType.FOREMAN, 1), (WorkerType.JOURNEYMAN, 5), (WorkerType.LABORER, 3)]
large_crew = self.build_crew("Large Crew", trade, large_workers, 2.0)
crews.append(large_crew)
# Calculate metrics for each crew
results = []
for crew in crews:
# Adjusted productivity considering crew efficiency
crew_workers = sum(count for _, count in crew.workers)
efficiency = self._crew_efficiency(crew_workers)
effective_productivity = crew.base_productivity * efficiency
hours_needed = total_hours / effective_productivity
days_needed = hours_needed / self.HOURS_PER_DAY
labor_cost = hours_needed * crew.hourly_cost
cost_per_unit = labor_cost / quantity if quantity > 0 else 0
results.append({
'crew': crew,
'days': days_needed,
'cost': labor_cost,
'cost_per_unit': cost_per_unit,
'efficiency': efficiency
})
# Select best crew based on target
if target_days:
# Find crew that meets target with lowest cost
valid = [r for r in results if r['days'] <= target_days]
if valid:
best = min(valid, key=lambda x: x['cost'])
else:
best = min(results, key=lambda x: x['days'])
else:
# Optimize for cost
best = min(results, key=lambda x: x['cost'])
recommended = best['crew']
alternatives = [r['crew'] for r in results if r['crew'] != recommended]
return CrewOptimizationResult(
work_item=work_item_code,
quantity=quantity,
unit=unit,
recommended_crew=recommended,
alternative_crews=alternatives,
duration_days=round(best['days'], 1),
total_labor_cost=round(best['cost'], 2),
cost_per_unit=round(best['cost_per_unit'], 2)
)
def _detect_trade(self, code: str) -> Trade:
"""Detect trade from work item code."""
code_lower = code.lower()
trade_map = {
'conc': Trade.CONCRETE,
'carp': Trade.CARPENTRY,
'mason': Trade.MASONRY,
'steel': Trade.STEEL,
'strl': Trade.STEEL,
'elec': Trade.ELECTRICAL,
'plumb': Trade.PLUMBING,
'hvac': Trade.HVAC,
'paint': Trade.PAINTING,
'roof': Trade.ROOFING
}
for key, trade in trade_map.items():
if key in code_lower:
return trade
return Trade.GENERAL
def _crew_efficiency(self, crew_size: int) -> float:
"""Calculate crew efficiency based on size (law of diminishing returns)."""
if crew_size <= 4:
return 1.0
elif crew_size <= 6:
return 0.95
elif crew_size <= 8:
return 0.90
elif crew_size <= 10:
return 0.85
else:
return 0.80
def analyze_overtime(self,
result: CrewOptimizationResult,
available_days: int,
max_overtime_hours: float = 2) -> Dict[str, Any]:
"""Analyze if overtime can meet schedule."""
if result.duration_days <= available_days:
return {
'overtime_needed': False,
'regular_days': result.duration_days,
'overtime_hours': 0,
'overtime_cost': 0,
'total_cost': result.total_labor_cost
}
# Calculate overtime needed
regular_hours = available_days * self.HOURS_PER_DAY
total_hours_available = available_days * (self.HOURS_PER_DAY + max_overtime_hours)
labor_norm, _ = self.get_labor_norm(result.work_item)
total_hours_needed = result.quantity * labor_norm / result.recommended_crew.base_productivity
if total_hours_needed > total_hours_available:
# Can't meet schedule even with overtime
overtime_hours = available_days * max_overtime_hours
shortage = total_hours_needed - total_hours_available
else:
overtime_hours = total_hours_needed - regular_hours
shortage = 0
overtime_cost = overtime_hours * result.recommended_crew.hourly_cost * 1.5
return {
'overtime_needed': True,
'regular_days': available_days,
'overtime_hours_per_day': max_overtime_hours,
'total_overtime_hours': round(overtime_hours, 1),
'overtime_cost': round(overtime_cost, 2),
'total_cost': round(result.total_labor_cost + overtime_cost, 2),
'shortage_hours': round(shortage, 1) if shortage > 0 else 0,
'can_meet_schedule': shortage == 0
}
def export_crew_plan(self,
results: List[CrewOptimizationResult],
output_path: str) -> str:
"""Export crew plan to Excel."""
with pd.ExcelWriter(output_path, engine='openpyxl') as writer:
# Summary
summary_data = []
for r in results:
workers_str = ", ".join(f"{count}x {wt.value}" for wt, count in r.recommended_crew.workers)
summary_data.append({
'Work Item': r.work_item,
'Quantity': r.quantity,
'Unit': r.unit,
'Crew': r.recommended_crew.name,
'Workers': workers_str,
'Duration Days': r.duration_days,
'Labor Cost': r.total_labor_cost,
'Cost/Unit': r.cost_per_unit
})
summary_df = pd.DataFrame(summary_data)
summary_df.to_excel(writer, sheet_name='Crew Plan', index=False)
# Totals
totals_df = pd.DataFrame([{
'Total Duration': max(r.duration_days for r in results),
'Total Labor Cost': sum(r.total_labor_cost for r in results)
}])
totals_df.to_excel(writer, sheet_name='Totals', index=False)
return output_pathQuick Start
# Load CWICR data
cwicr = pd.read_parquet("ddc_cwicr_en.parquet")
# Initialize optimizer
optimizer = CWICRCrewOptimizer(cwicr)
# Optimize crew for work item
result = optimizer.optimize_for_work(
work_item_code="CONC-SLAB-001",
quantity=500, # m2
target_days=10
)
print(f"Recommended: {result.recommended_crew.name}")
print(f"Duration: {result.duration_days} days")
print(f"Labor Cost: ${result.total_labor_cost:,.2f}")Common Use Cases
1. Meet Schedule with Overtime
overtime = optimizer.analyze_overtime(result, available_days=8)
print(f"Overtime needed: {overtime['overtime_needed']}")
print(f"Total cost: ${overtime['total_cost']:,.2f}")2. Compare Crews
for crew in [result.recommended_crew] + result.alternative_crews:
print(f"{crew.name}: ${crew.hourly_cost}/hr")3. Custom Crew
custom = optimizer.build_crew(
name="Custom Concrete",
trade=Trade.CONCRETE,
workers=[
(WorkerType.FOREMAN, 1),
(WorkerType.JOURNEYMAN, 4),
(WorkerType.LABORER, 2)
],
base_productivity=1.5
)Resources
- GitHub: OpenConstructionEstimate-DDC-CWICR
- DDC Book: Chapter 3.1 - Crew Productivity Analysis