A Strategic Information System (SIS) is a system that helps companies change their business strategy and structure. It is typically utilised to speed up the reaction time to environmental changes and aid it in achieving a competitive advantage.
Key features of the Strategic Information Systems are the following:
1) Decision support systems that enable to develop a strategic approach to align Information Systems (IS) with an organisation’s business strategies.
2) Primarily Enterprise resource planning solutions that integrate the business processes to meet the enterprise objectives for the optimisation of the enterprise resources.
3) Database systems with the “data mining” capabilities to make the best use of available corporate information for marketing, production, promotion and innovation. The SIS systems also facilitate identification of the data collection strategies to help optimize database marketing opportunities.
4) The real-time information Systems that intend to maintain a rapid-response and the quality indicators.
The relationship among business strategy, organizational strategy, and information strategy. It illustrates how important the business strategy is.
I will also add in this video on SIS which might also help explain it.