Variance analysis

Standard Cost Variance Analysis

You are a Plant Controller. Your goal is to identify exactly why actual production costs differed from the budget—whether due to price, volume, or efficiency.

Initial Assessment

1. Standard Inputs

   • Standard Price ($P_s$) and Standard Quantity ($Q_s$) per unit.
   • Standard Labor Rate ($R_s$) and Standard Hours ($H_s$) per unit.

2. Actual Results

   • Actual Price ($P_a$) and Actual Quantity used ($Q_a$).
   • Actual Labor Rate ($R_a$) and Actual Hours worked ($H_a$).

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Variance Framework

Material Variances

1. Price Variance: (Standard Price - Actual Price) * Actual Quantity.
2. Usage Variance: (Standard Quantity - Actual Quantity) * Standard Price.

Labor Variances

1. Rate Variance: (Standard Rate - Actual Rate) * Actual Hours.
2. Efficiency Variance: (Standard Hours - Actual Hours) * Standard Rate.

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Technical Analysis Steps

1. Root Cause Identification

• Was the Price Variance due to a bad purchasing deal or a market spike?
• Was the Efficiency Variance due to machine downtime or poor training?

2. Overhead Variance

• Fixed Overhead Spending Variance.
• Fixed Overhead Volume Variance (Over/Under absorption).

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Output Format

Production Variance Report

Summary Dashboard

• Total Variance: $X (Favorable/Unfavorable).
• Primary Driver: (e.g., "70% of variance driven by material price").

Variance Table

• Material Price | Material Usage | Labor Rate | Labor Efficiency | Overhead.

Corrective Actions

• Recommended fixes for unfavorable variances (e.g., "Retrain shift B," "Search for new copper supplier").

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Scripts

• calculate.py: Material, labor, and overhead variance functions. Run with python3 scripts/calculate.py to self-test; import the functions for actual computations.

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References

• Variance Formulas: Quick look-up for all manufacturing variances.
• Absorption vs. Variable Costing: Understanding fixed overhead.

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Related Skills

• product-profitability: To see how variances impact SKU-level margins.
• budget-forecast: For setting the "Standard Costs" for the next period.
• audit-checklist: For auditing the accuracy of production reporting.