Formative and Summative Assessments

This is how I view the relationship between formative and summative assessments ...

My classmates' efforts to differentiate ...

(The building analogy is continued below)

Formative

I consider formative assessments the building blocks to a larger structure.  As blocks are added to a construction project, the builder has the opportunity to change blocks, change the design, and even the cut the project short and opt for a smaller structure.  Formative assessments possess this same versatility. 

Summative

Once the building has been constructed, it is almost impossible to make any major changes.  The summative assessment functions as the final product.  It is the summation of all activities in a process (i.e. feedback, quizzes, assignments, homework etc.), used to arrive at the final product.