Process of Decision Making in a company can be classified as follows : Strategic Decision Making (Determines long-term objectives, resources, and policies), Management Control (Monitors effective or efficient usage of resources and performance of operational units), Operational control (Determines how to perform specific tasks set by strategic and middle-management decision makers), and Knowledge-Level Decision Making (Evaluates new ideas for products, services, ways to communicate new knowledge, ways to distribute information).
Decisions are classified as : Unstructured (Non routine, decision maker provides judgment, evaluation, and insights into problem definition, no agreed-upon procedure for decision making), and Structured (Repetitive, routine, handled using a definite procedure).
TPS = Transaction Processing Systems
OAS = Office Automtic Systems
MIS = Management Information Systems
DSS = Decision Support Systems
KWS = Knowledge Work Systems
ESS = Knowledge Work Systems