difinition:
The strategic grid model is an IT specific model that can be used to assess the nature of the projects that the IT organization has in its portfolio with the aim of seeing how well that portfolio supports the operational and strategic interests of the firm.

the application of systematic management to large classes of items managed by enterprise information technology capabilities. Examples of IT portfolios would be planned initiatives, projects, and ongoing IT services.

purpose:

it is the biggest advantage over investment approaches and methods. Other objectives include central oversight of budget, risk management, strategic alignment of IT investments, demand and investment management along with standardization of investment procedure, rules and plans.

application:

Management of this portfolio focuses on comparing spending on established systems based upon their relative value to the organization. The comparison can be based upon the level of contribution in terms of IT investment’s profitability. Additionally, this comparison can also be based upon the non-tangible factors such as organizations’ level of experience with a certain technology, users’ familiarity with the applications and infrastructure, and external forces such as emergence of new technologies and obsolesce of old ones.