ABC and VED analysis

Selective inventory control: ABC classification by annual consumption value, VED by criticality, the ABC-VED matrix, other classifications (FSN, HML, SDE, XYZ) and control policies by class.

Drafted with Aria, reviewed by the AiCanCode.org team. Spotted an error? Use Give Feedback at the bottom of the page.

Why it matters

A medium-sized engineering plant may stock 10,000 different items, from castings worth lakhs to washers worth paise. Nobody can give each one the same attention. Selective inventory control classifies items so that tight control, frequent review and accurate records go where the money is (ABC) and where a stock-out would stop the plant (VED), while cheap, non-critical items are handled with simple rules.

Key ideas

ABC analysis (Pareto analysis, "always better control"). Items are ranked by annual consumption value = annual usage (units) × unit cost (₹). A few items account for most of the money – the Pareto principle. Steps:

  1. For each item compute annual consumption value.
  2. Rank items in decreasing order of value.
  3. Compute each item's percentage of total value and the cumulative percentage, together with the cumulative percentage of items.
  4. Draw cut-offs. A typical pattern:
    • A items: about 10–20 % of items, about 70–80 % of value.
    • B items: about 20–30 % of items, about 15–25 % of value.
    • C items: about 50–70 % of items, about 5–10 % of value. The cut-offs are a management judgment, not fixed numbers; plotting cumulative % value against cumulative % items (the Pareto or ABC curve) helps locate the "knee".

Control policies by class.

  • A: tight control by senior staff, accurate perpetual records, frequent review, small and frequent orders (low cycle stock), low safety stock with close follow-up, value analysis and negotiation, cycle counting perhaps monthly.
  • B: moderate control, EOQ-based ordering, periodic review, cycle counting quarterly.
  • C: simple rules (two-bin system, bulk orders, larger safety stock is cheap), counting once or twice a year.

Limitations of ABC. It looks only at money. A cheap O-ring may stop a production line. Annual value also changes over time, so classes must be revised periodically.

VED analysis (criticality). Classifies items by the consequence of a stock-out, mainly for spares:

  • Vital (V) – a shortage stops production or creates a safety hazard; must always be available, high safety stock.
  • Essential (E) – a shortage causes significant loss of efficiency or a temporary disruption, but not a complete stoppage; moderate safety stock.
  • Desirable (D) – a shortage causes little or no immediate effect on production; minimal stock. VED is based on expert judgment of maintenance and production staff, not on a calculation.

ABC–VED matrix. Combining the two gives nine cells, usually grouped into three control categories:

  • Category I (AV, AE, BV, CV) – the highest attention: either costly or critical.
  • Category II (AD, BE, CE) – moderate attention.
  • Category III (BD, CD) – the least attention. For example, a CV item (cheap but vital) is stocked generously because doing so costs little, while an AD item (expensive but non-critical) is held at minimum.

Other selective-control classifications.

  • FSN – Fast, Slow, Non-moving (by issue frequency); helps find obsolete stock.
  • HML – High, Medium, Low unit price (not annual value).
  • SDE – Scarce, Difficult, Easy to procure (by availability).
  • XYZ – by value of inventory actually held in stock (closing stock), not annual consumption.
  • GOLF – Government, Ordinary, Local, Foreign sources; SOS – Seasonal, Off-seasonal.

Formulas

Annual consumption value (ACV) of item i = Dᵢ · Cᵢ

  • Dᵢ = annual usage (units/year), Cᵢ = unit cost (₹/unit); ACV in ₹/year.

% value of item i = 100 · ACVᵢ / Σ ACV Cumulative % value (after ranking) = 100 · Σ (ACV of items ranked 1 … k) / Σ ACV Cumulative % items = 100 · k / n

  • k = rank, n = total number of items.

Annual cycle counts = Σ (number of items in class × counts per year for class)

  • Workload for cycle counting; divide by working days to get counts per day.

Worked examples

Example 1 (standard) – ABC classification of 10 items. Annual usage (units) × unit cost (₹): item 1: 500 × 120; item 2: 2000 × 5; item 3: 100 × 900; item 4: 1500 × 2; item 5: 800 × 40; item 6: 4000 × 1; item 7: 250 × 60; item 8: 3000 × 1.5; item 9: 600 × 10; item 10: 1200 × 2.

  1. Annual values (₹): 1: 60,000; 2: 10,000; 3: 90,000; 4: 3000; 5: 32,000; 6: 4000; 7: 15,000; 8: 4500; 9: 6000; 10: 2400. Total = ₹2,26,900.
  2. Ranked with cumulative %: item 3 (39.7 %, cum 39.7 %), item 1 (26.4 %, 66.1 %), item 5 (14.1 %, 80.2 %), item 7 (6.6 %, 86.8 %), item 2 (4.4 %, 91.2 %), item 9 (2.6 %, 93.9 %), item 8 (2.0 %, 95.9 %), item 6 (1.8 %, 97.6 %), item 4 (1.3 %, 98.9 %), item 10 (1.1 %, 100 %).
  3. A = items 3, 1, 5 (30 % of items, 80.2 % of value); B = items 7, 2 (20 % of items, 11.0 % of value); C = items 9, 8, 6, 4, 10 (50 % of items, 8.8 % of value).
  4. Note that item 6 has the highest usage (4000 units) but is a C item – ABC uses value, not quantity.

Example 2 (GATE level) – cycle-counting workload and the ABC–VED matrix. A stores holds 2000 items: 10 % are A, 30 % B and 60 % C. Policy: count A items monthly, B quarterly and C twice a year. The store works 240 days a year.

  1. Items: A = 200, B = 600, C = 1200.
  2. Counts per year = 200 × 12 + 600 × 4 + 1200 × 2 = 2400 + 2400 + 2400 = 7200.
  3. Counts per day = 7200/240 = 30 items per day.
  4. A spare bearing costs ₹40 (C item) but its absence stops the main compressor (V). It is a CV item – Category I: keep a generous safety stock, since the holding cost is small and the stock-out cost is large. A ₹2 lakh decorative display panel (A item, D criticality) is AD – Category II: hold none or the minimum and order when required.

Common mistakes

  • Ranking by unit cost or by quantity instead of by annual consumption value (unit cost alone is HML analysis).
  • Forgetting to sort before computing cumulative percentages.
  • Treating 80/20 cut-offs as exact laws.
  • Applying the same safety-stock policy to all A items regardless of criticality.
  • Confusing VED (criticality) with FSN (movement) or SDE (procurement difficulty).
  • Never reclassifying: prices and usage change, so ABC classes drift.

For GATE PI

Expect a table of items with usage and unit cost, asking which items fall in class A or what percentage of total value a class represents; matching of classification systems (ABC, VED, FSN, HML, SDE, XYZ) with their basis; and policy questions (which class gets tight control, two-bin system, etc.). Practise building the ranked cumulative table quickly.

Quick check

  1. Item P: 400 units/year at ₹25; item Q: 50 units/year at ₹150. Which has the higher annual consumption value?
  2. What is the basis of HML classification?
  3. A cheap item whose shortage stops the plant falls in which ABC–VED cell, and which category?
  4. Which analysis identifies obsolete stock?

Answers: 1. P (₹10,000 vs ₹7500). 2. Unit price of the item. 3. CV, Category I. 4. FSN analysis (non-moving items).

Interview questions

All Production Planning and Operations Management interview questions

Try answering each one aloud before you open it.

  1. 1.What is ABC analysis in inventory management?Concept

    ABC analysis is an inventory categorization technique where items are divided into three categories: A, B, and C. 'A' items are the most valuable, typically representing a small percentage of the total items but a large portion of the inventory value. 'B' items are of moderate value, and 'C' items are the least valuable, often representing a large percentage of the total items but a small portion of the inventory value. This helps prioritize management focus and resources.

  2. 2.Explain VED analysis and its importance in inventory management.Concept

    VED analysis categorizes inventory items based on their criticality to the production process: Vital, Essential, and Desirable. 'Vital' items are crucial for production and their absence can halt operations. 'Essential' items are important but not critical, while 'Desirable' items are the least critical. This analysis helps in prioritizing inventory control and ensuring that critical items are always available.

  3. 3.How do ABC and VED analyses differ in their approach to inventory management?Concept

    ABC analysis focuses on the financial value of inventory items, categorizing them based on their contribution to the overall inventory cost. In contrast, VED analysis categorizes items based on their criticality to the production process. While ABC helps in financial prioritization, VED ensures operational continuity by focusing on the availability of critical items.

  4. 4.Why is ABC analysis used in inventory management?Application

    ABC analysis is used to prioritize inventory management efforts by identifying the most valuable items that require more attention and control. By focusing on 'A' items, companies can optimize their inventory costs and improve cash flow. It helps in efficient resource allocation, ensuring that the most impactful items are managed effectively.

  5. 5.What happens if a company ignores VED analysis in its inventory management?Application

    Ignoring VED analysis can lead to stockouts of critical items, potentially halting production and causing significant operational disruptions. Without understanding the criticality of items, a company may overstock less important items while understocking vital ones, leading to inefficiencies and increased costs.

  6. 6.How can ABC and VED analyses be combined for more effective inventory management?Application

    Combining ABC and VED analyses allows a company to prioritize inventory based on both financial value and criticality. This dual approach ensures that high-value and critical items are managed with the highest priority, optimizing both cost and operational efficiency. It helps in making informed decisions about stocking levels and resource allocation.

  7. 7.In what scenarios would a company prioritize VED analysis over ABC analysis?Application

    A company might prioritize VED analysis over ABC analysis in scenarios where operational continuity is more critical than cost, such as in healthcare or manufacturing industries where the absence of vital items can lead to severe consequences. In such cases, ensuring the availability of critical items takes precedence over cost considerations.

  8. 8.A company has 1000 inventory items. If 'A' items represent 10% of the items and 'C' items represent 50%, how many items are in each category?Numerical

    For 'A' items: 10% of 1000 = 100 items. For 'C' items: 50% of 1000 = 500 items. The remaining items are 'B' items: 1000 - 100 - 500 = 400 items.

  9. 9.What are the potential drawbacks of relying solely on ABC analysis for inventory management?Application

    Relying solely on ABC analysis can lead to neglecting the criticality of items, as it focuses only on financial value. This might result in stockouts of critical items that are not high-value but essential for operations. Additionally, it may not account for changes in demand patterns or supply chain disruptions, leading to inefficiencies.

Finished this topic? Mark it so your progress, study plan and readiness keep up.

Stuck on something here?

PreviousSafety stock and reorder point under uncertaintyNext Just-in-time and kanban