From Edutopia: Efficient Ways to Check for Understanding

What strategy can double student learning gains? According to 250 empirical studies, the answer is formative assessment, defined by Bill Younglove as "the frequent, interactive checking of student progress and understanding in order to identify learning needs and adjust teaching appropriately."

Unlike summative assessment, which evaluates student learning according to a benchmark, formative assessment monitors student understanding so that kids are always aware of their academic strengths and learning gaps. Meanwhile, teachers can improve the effectiveness of their instruction, re-teaching if necessary. "When the cook tastes the soup," writes Robert E. Stake, "that's formative; when the guests taste the soup, that's summative." Formative assessment can be administered as an exam. But if the assessment is not a traditional quiz, it falls within the category of alternative assessment.

To see 53 Ways to Check for Understanding, click here. (In my opinion, this is the BEST and MOST CLARIFYING article I have read on formative assessment.)