Rolled Throughput Yield (RTY) is the cumulative probability of passing all process steps without defects — calculated by multiplying individual step yields, revealing true process capability better than final yield alone since it accounts for hidden rework.

What Is RTY?

• Definition: Product of all individual process step yields.
• Formula: RTY = Y₁ × Y₂ × Y₃ × ... × Yₙ
• Purpose: Measure true first-time-through capability.
• Insight: Reveals hidden rework and inefficiency.

Why RTY Matters

• True Capability: Shows actual first-pass success rate across entire flow.
• Hidden Factory: Exposes rework loops not visible in final yield.
• Cost Impact: Lower RTY means more rework, higher cost.
• Bottleneck Identification: Pinpoints weakest process steps.
• Improvement Focus: Guides where to focus improvement efforts.

Calculation

def calculate_rty(step_yields):
    rty = 1.0
    for yield_value in step_yields:
        rty *= yield_value
    return rty * 100

# Example
steps = [0.98, 0.95, 0.97, 0.99, 0.96]  # 5 process steps
rty = calculate_rty(steps)
print(f"RTY: {rty:.1f}%")  # 85.7%

RTY vs Final Yield

• Final Yield: 95% (after rework)
• RTY: 85% (true first-pass)
• Difference: 10% hidden rework

Improvement Strategy: Focus on lowest-yield steps first for maximum RTY improvement.

RTY is the truth teller — revealing the real efficiency of manufacturing by accounting for all rework, making it essential for identifying true improvement opportunities.