Multiphase Programmatic Approach (MPA) of World Bank allows countries the flexibility to implement an approach to achieve development objectives in stages when:  

• the development challenge is complex;  
• it would take a longer time to achieve the objectives;  

• it would take a longer time to prepare one large project;  
• the solution needs a broader and comprehensive approach;  
• when a stop-and-go approach is not feasible.  

Projects under an MPA program may be financed by Investment Project Financing; or Program-for-Results financing, or their combination.  

Source: https://www.worldbank.org/en/projects-operations/products-and-services#MPA