What is departmentation, and which patterns are commonly used?

Question

Accepted Answer

Departmentation is the process of grouping activities into organizational units — by function, product/service, location, time, or process/equipment.
It serves specialization and fixation of responsibility (you know who owns what). The five classic patterns:

Pattern
Example

By function
Production, Marketing, Finance, HR, IT

By product or service
Business unit per product line

By location/territory
Region EMEA, Americas, Asia-Pacific

By time
Shift 1, Shift 2, Shift 3 (e.g. a 24/7 SOC!)

By process and equipment
Casting shop, machining, assembly

It distinguishes basic functions (directly serving the mission) from secondary functions (supporting them).
Tip: A Security Operations Center is a beautiful triple example: departmented by function (security), often by time (follow-the-sun shifts), and sometimes by location (regional SOCs).
Go deeper:

Departmentalization (Wikipedia) — the grouping patterns (function, product, territory, process) with examples.

Pattern	Example
By function	Production, Marketing, Finance, HR, IT
By product or service	Business unit per product line
By location/territory	Region EMEA, Americas, Asia-Pacific
By time	Shift 1, Shift 2, Shift 3 (e.g. a 24/7 SOC!)
By process and equipment	Casting shop, machining, assembly