Step 1: Meaning:
Delegation is the transfer of authority by an individual superior to an individual subordinate for a specific task. Decentralisation is the systematic dispersal of authority throughout the organisation to all levels of management — essentially, decentralisation is delegation extended to the lowest levels.
Step 2: Scope:
Delegation is relevant between a superior and their immediate subordinate (a relatively narrow, two-person relationship); decentralisation is a companywide philosophy applied across departments and hierarchy levels.
Step 3: Nature:
Delegation is a compulsory act — every manager who wants work done through others must delegate at least some authority. Decentralisation is an optional policy decision taken by top management.
Step 4: Freedom of action:
Under delegation, the subordinate exercises authority under the superior's close supervision. Under decentralisation, lower-level managers enjoy substantial freedom to act and decide independently within delegated limits.
Step 5: Purpose:
Delegation aims to lighten a single superior's workload for a specific task. Decentralisation aims to build overall organisational capability and to develop future managers by giving many people decision-making practice.
Final Answer:
Delegation is authority transfer between two individuals for a specific task and is compulsory; decentralisation is the systematic spreading of authority across the whole organisation and is an optional top-management policy.