[1.2.3b] Economies & diseconomies of scale

Economies of Scale

Economies of scale occur when a firm's average cost of production falls as its scale of output increases in the long run. Larger firms can produce each unit more cheaply than smaller ones. This is one of the main incentives for firms to grow.

Economies of scale can arise from factors internal to the firm (internal economies) or from the broader environment in which the firm operates (external economies).

Internal Economies of Scale

Internal economies arise from the growth of the firm itself.

Purchasing (bulk buying): large firms buy raw materials in bulk and negotiate significant discounts from suppliers. A major supermarket chain negotiates far lower prices than an independent shop, giving it a cost advantage on every product sold.

Marketing: a national advertising campaign costs the same whether it reaches customers buying 1,000 or 1,000,000 units. Marketing cost per unit falls sharply as output grows. Large firms can also afford dedicated specialist marketing departments.

Technical: larger firms can invest in expensive specialist machinery that smaller firms cannot justify. A large car manufacturer uses robotic assembly lines; a small workshop uses manual labour. The result is dramatically lower cost per unit. Fixed capital costs are also spread over more units.

Financial: large firms can borrow at lower interest rates — banks regard them as lower default risk. Lower borrowing costs reduce financial overheads per unit of output.

Managerial: as a firm grows, it can justify employing specialist managers — a dedicated finance director, HR specialist, logistics manager. These professionals are far more efficient than a generalist manager covering everything. Specialist management cost is spread over higher output.

Risk bearing: large firms spread risk across multiple products, markets and geographies. A conglomerate selling across sectors is less exposed to a downturn in any one area, reducing the risk of catastrophic failure.

External Economies of Scale

External economies arise from the growth of the industry as a whole, benefiting all firms within it.

  • Skilled labour: as an industry concentrates in a region, local institutions develop relevant training, creating a pool of specialist workers. Firms can recruit trained staff without bearing the full training cost.
  • Infrastructure: a thriving industrial cluster attracts investment in roads, ports and utilities that serve all firms in the area.
  • Access to suppliers: specialist component manufacturers and logistics firms set up near a major cluster, reducing input costs and delivery times for all firms.
  • Similar businesses in the area: knowledge spillovers, shared R&D facilities and informal networks accelerate innovation and reduce costs. Silicon Valley and the City of London are classic examples.

Diseconomies of Scale

Diseconomies of scale occur when a firm grows beyond its optimal size and average costs begin to rise. They arise from the management challenges of running a very large firm.

  • Bureaucracy: layers of management, approval processes and administration slow decision-making and add overhead without adding value.
  • Communication problems: information passes through many management layers; messages distort, decisions delay and front-line feedback fails to reach senior decision-makers in time.
  • Lack of control: senior management cannot monitor all activity across all divisions. Inconsistencies, inefficiencies and misconduct can go undetected.
  • Distance between top management and workers: workers at the bottom of a large hierarchy feel disconnected from the firm's mission, reducing motivation, commitment and productivity.

The Long Run Average Cost (LRAC) Curve

The LRAC curve is typically U-shaped, reflecting economies of scale (falling ATC), a minimum efficient scale (lowest ATC), then diseconomies of scale (rising ATC).

Output (Q) Average Cost (£) LRAC Q* Min. efficient scale Economies of scale ↓ Diseconomies of scale ↑

At Q* (minimum efficient scale), the firm operates at its lowest possible average cost — the most productively efficient point.

 Key Takeaways

  • Economies of scale: ATC falls as output increases in the long run.
  • Internal economies arise from firm growth: purchasing, marketing, technical, financial, managerial and risk-bearing.
  • External economies arise from industry growth: skilled labour, infrastructure, supplier access and cluster benefits.
  • Diseconomies of scale: ATC rises beyond optimal scale due to bureaucracy, communication problems, lack of control and management distance.
  • The LRAC curve is U-shaped; the lowest point is the minimum efficient scale.
b) Economies of scale: • definition of economies of scale • definition of internal economies of scale • types of internal economies of scale: o purchasing (bulk buying) o marketing o technical o financial o managerial o risk bearing. • definition of external economies of scale • types of external economies of scale: o skilled labour o infrastructure o access to suppliers o similar businesses in area. c) Diseconomies of scale: • definition of diseconomies of scale • types of diseconomies of scale: o bureaucracy o communication problems o lack of control o distance between top management and workers at bottom of the organisation • the use of long run average cost (LRAC) curve diagram, annotated to show internal economies of scale and diseconomies of scale and where the business will be most efficient.