MA Standard Cost Variance

標準原価差異分析スキル。標準原価（予定原価）と実際原価の差異を価格差異・数量差異に分解し、 材料費・労務費・製造間接費のカテゴリ別に集計・分析する。差異の有利/不利判定、 責任部門の特定、根本原因の仮説提示を行う。CSVデータのアップロードによる自動分析に対応。

Use when: 製造原価の差異分析を行いたいとき。標準原価計算制度の運用、 月次原価差異レポート作成、原価低減活動の効果測定に使用。

Triggers: “標準原価”, “原価差異”, “価格差異”, “数量差異”, “standard cost”, “cost variance”, “price variance”, “quantity variance”, “予定原価”, “操業度差異”, “原価管理”

No API Required

Download Skill Package (.skill) View Source on GitHub

Table of Contents

1. Overview

Analyzes the differences between standard (planned) and actual costs, decomposing variances into price and quantity components. Identifies responsible departments and provides root cause hypotheses for manufacturing cost management.

2. Prerequisites

Before running this skill, ensure the following data is available:

  • Standard Cost Data: Standard price and standard quantity per item
  • Actual Cost Data: Actual price and actual quantity per item
  • Cost Category Classification: Each item classified as material, labor, or overhead
  • Period Information: Target analysis period

Required CSV Format 

item_name,cost_category,standard_price,actual_price,standard_quantity,actual_quantity
Eggs,material,2.50,3.20,100,105
Line Worker,labor,25.00,26.50,40,42
Equipment Depreciation,overhead,5000,5000,1,1

Required Columns: | Column | Type | Description | |——–|——|————-| | item_name | string | Cost item name | | cost_category | string | material, labor, or overhead | | standard_price | numeric | Standard (planned) unit price | | actual_price | numeric | Actual unit price | | standard_quantity | numeric | Standard quantity for actual output | | actual_quantity | numeric | Actual quantity consumed |

Cost Categories

  • material: Raw materials and components (e.g., flour, eggs, packaging)
  • labor: Direct labor (e.g., line workers, supervisors)
  • overhead: Manufacturing overhead (e.g., depreciation, utilities, maintenance)

3. Quick Start

  1. Validate Input Format: Verify CSV structure and required columns
  2. Classify Cost Items: Confirm cost category assignments (material/labor/overhead)
  3. Verify Standard Costs: Ensure standard costs reflect current approved standards
  4. Handle Edge Cases: Address zero quantities, missing prices, and new items without standards

4. How It Works

  1. Validate Input Format: Verify CSV structure and required columns
  2. Classify Cost Items: Confirm cost category assignments (material/labor/overhead)
  3. Verify Standard Costs: Ensure standard costs reflect current approved standards
  4. Handle Edge Cases: Address zero quantities, missing prices, and new items without standards

5. Usage Examples

  • Monthly Cost Variance Reporting - Analyze standard vs. actual cost differences for manufacturing operations
  • 「今月の原価差異を分析して」「標準原価との乖離を計算して」
  • Cost Reduction Effectiveness Measurement - Evaluate whether cost reduction initiatives achieved target
  • 「原価低減活動の効果を測定して」「コスト削減の進捗を確認して」
  • Procurement Price Monitoring - Track material price variances against standards
  • 「材料の価格差異を確認して」「仕入価格の変動を分析して」

6. Understanding the Output

The analysis produces a structured cost variance report containing:

  1. Executive Summary: Total variance by category, key highlights
  2. Item-Level Detail: Price variance, quantity variance, and total per item with calculation basis
  3. Category Subtotals: Aggregated variances by material/labor/overhead
  4. Responsibility Matrix: Variance amounts mapped to responsible departments
  5. Root Cause Analysis: Hypotheses and recommended actions for major variances

Output template: assets/cost_variance_report_template_ja.md (Japanese) or assets/cost_variance_report_template_en.md (English)

7. Tips & Best Practices

  • Begin with the smallest realistic sample input so you can validate the workflow before scaling up.
  • Keep skills/ma-standard-cost-variance/SKILL.md open while working; it remains the authoritative source for the full procedure.
  • Review the most relevant reference files first instead of scanning every guide: 第11回_ABCで見える店舗別損益管理の真実_20251213.md, 第12回_予定原価という考え方_20260122.md.
  • Preserve intermediate outputs so you can explain assumptions, diffs, and follow-up actions clearly.

8. Combining with Other Skills

  • Combine this skill with adjacent skills in the same category when the work spans planning, implementation, and review.
  • Browse the broader category for neighboring workflows: category index.
  • Use the English skill catalog when you need to chain this workflow into a larger end-to-end process.

9. Troubleshooting

  • Re-check prerequisites first: missing runtime dependencies and unsupported file formats are the most common failures.
  • If a helper script is involved, run it with a minimal sample input before applying it to a full dataset or repository.
  • Compare your input shape against the reference files to confirm expected fields, sections, or metadata are present.

10. Reference

References:

  • skills/ma-standard-cost-variance/references/第11回_ABCで見える店舗別損益管理の真実_20251213.md
  • skills/ma-standard-cost-variance/references/第12回_予定原価という考え方_20260122.md