Information systems support different types of decisions at different levels of the organizational hierarchy. Major types of Information systems include structural databases and information management software that can include the following;

• Transaction Process Systems (TPS)
• Enterprise Collaboration Systems (ECS)
• Management Information Systems (MIS)
• Decision Support Systems (DSS)
• Executive Support Systems (ESS)

ION501: Types of Information Systems
While operational managers mostly make structured decisions, senior managers deal with unstructured decisions; middle managers are often faced with semi-structured decisions.