Summative Assessment, as the name might imply, is the end-of-it-all assessment to measure student growth from the beginning of a learning segment to the end. Summative assessments, traditionally, come in the forms of things like big tests, essays, projects, and --of course-- standardized tests.
There is some controversy surrounding summative assessments and exactly how summative they should be. If the move towards formative assessment is to be authentic, then shouldn't we give students opportunities, even with huge 100 point tests, to redo and do better? At the same time, shouldn't there be a line in the sand wherein students face the "real world" phenomenon of being unable to redo something? And what about end-of-the-year assessments and major projects that determine the student's semester grade? In that case, formative feedback won't do any good because the students won't even be in the class anymore. And often times, with standardized testing, the student (or teacher!) never see the actual individual results, just some vaguely explained score that ranks the school as a whole. And with standardized testing, exactly how accurately does that reflect student growth? Some students are terrible test-takers, and some standardized tests are terrible at assessing students, either due to the lack of relevancy or the lack of customized student growth recognition-- which another controversy entirely.
And so on.
The moral of the story is that both forms of assessment have their place and serve their two similar, but distinct, purposes. Just as formative assessment is an indicator to the teacher as to what aid their student needs and provides a chance to provide that aid and redirect current teachings so as to better create understanding among the students, so too does summative assessment serve its purpose in being a final measure of student growth.