Here are some of the assessment and appraisal models which are recommended in the context of "Software Process Improvement".

• SPICE (Software Process Improvement Capability dEtermination)
  
  

  SPiCE is the name of a project, that lead to the development of the standard "ISO/IEC TR 15504 (Software Process Assessment)" (currently a "Technical Report", within short it will be a "International Standard").
  
  

• CMMI (Capability Maturity Model Integration)

  The Capability Maturity Model Integration (CMMI) of the Software Engineering Institute (SEI) is a model suitable for process improvement. It is the successor of the SW-CMM model.