Define IS and its types

An Information System (IS) is an organised combination of people, hardware, software, data, networks and procedures that collects, processes, stores and distributes information to support operations, management and decision making in an organization.

Types of information systems

Information systems are grouped by the organizational level and the function they serve.

        /\
       /ESS\        Strategic level (top mgmt)
      /------\
     / DSS/MIS\     Management level
    /----------\
   /    TPS     \   Operational level
  ----------------

1. Transaction Processing System (TPS) - records and processes daily routine transactions (sales, payroll, billing, ATM withdrawals). It serves operational staff, and its output feeds other systems. Example: a bank's deposit and withdrawal system.
2. Office Automation / Knowledge Work System (OAS/KWS) - supports clerical and knowledge workers with word processing, email, scheduling and design tools (e.g. CAD).
3. Management Information System (MIS) - summarises TPS data into regular, structured reports (monthly sales, inventory status) for middle managers to monitor and control.
4. Decision Support System (DSS) - interactive system with models and data analysis tools that helps managers solve semi-structured problems, using "what-if" analysis. Example: a pricing model.
5. Executive Support System (ESS) - gives senior executives a quick, summarised, graphical view of internal and external data (dashboards, trends) for strategic, unstructured decisions.
6. Expert System / Knowledge-based System - captures expert knowledge as rules to give advice in a narrow area (e.g. loan approval, medical diagnosis).
7. Enterprise systems (ERP, CRM, SCM) - integrate business processes across departments and partners on a common database.

Support for business operations and decisions

• Operations: TPS, OAS, ERP automate routine work with speed and accuracy.
• Management decisions: MIS, DSS, ESS and expert systems provide information, models and advice at the right level.