The advantages of formative assessment are that they allow teachers to constantly gauge their students' progress, and as a result, students' test scores tend to go up, since teachers are able to adjust their lesson plans to accommodate what students are, and aren't learning.
(Wormelli, 2010).
The disadvantages of formative assessment are that they take up valuable class time which might be better spent teaching, rather than assessing, the topic. Is it also unclear how teachers may assign required grades throughout a unit, for smaller assignments, if there is an over-reliance on ungraded formative assessments.