The Why, What, and When of Assessment

Instructions: Follow the tabs to improve your reading comprehension and vocabulary development.

Various experts use three different prepositions to suggest purposes of assessment. They distinguish between assessment of instruction, assessment for instruction, and assessment as instruction (Chappius, Stiggins, Chappius, & Arter, 2012; Earl, 2003).

Students vary in at least three ways that affect learning: readiness, interest, and learning profile.

As you read the rest of the article below consider the meaning of the terms in bold.  Then go on to the next tab to check your understanding.

Effective differentiation requires teachers to assess student status before a unit of study begins (pre-assessment), throughout the unit of study (formative or ongoing assessment), and at key ending or wrap-up points in a unit of study (summative assessment). Pre- or diagnostic assessment helps determine a student's starting point with learning targets as well as with prerequisite knowledge, understandings, and skills that are essential to continued progress in a content sequence. Pre-assessment is also useful in developing awareness about students' interests and learning preferences. Formative (ongoing) assessment lets teachers closely monitor a student's evolving knowledge, understanding, and skills—including any misunderstandings a student may have or develop about key content. As with diagnostic or pre-assessment, formative assessment also plays a role in revealing students' various interests and approaches to learning. Summative assessment evaluates a student's status with the learning targets at designated endpoints or checkpoints in a unit of study—for example, at the end of a section of a unit, end of a marking period, end of a semester, midterm, and so on. Differentiation places particular emphasis on pre-assessment and formative assessment.

Assessment in an effectively differentiated classroom will be both informal and formal. Informal assessments include things like talking with students as they enter and leave the room, observing students as they work on a task or in groups, watching students on the playground or at lunch, asking students to use hand signals or colored cards to indicate their degree of confidence with a skill they have just practiced, or making note of informative comments made by parents at a back-to-school night. Informal assessments are useful in giving a teacher a sense of what makes a student tick, providing a big-picture look at how the class as a whole seems to be faring at a given moment, and amassing a growing sense of how specific students work in particular contexts. They are not as useful in revealing the status of each student in the class with regard to a particular learning target or set of learning targets. Formal assessments include things like surveys, quizzes, exit cards, Frayer diagrams, quick-writes, homework checks, purposeful note taking about students' proficiencies, interests, or learning approaches, and so on. Unlike informal assessments, formal assessments generally provide data from all students on a particular learning target or set of learning targets that a teacher can systematically study for purposes of instructional decision making—and that a student can examine relative to important learning goals.


Chappius, J., Stiggins, R., Chappius, S., & Arter, J. (2012). Assessment for learning: Doing it right, using it well (2nd ed.). Upper Saddle River, NJ: Pearson.

Earl, L. (2003). Assessment as learning: Using classroom assessment to maximize student learning. Thousand Oaks, CA: Corwin.


Tomlinson, C., & Moon, T. (2013, October 24).  ACSD. The Why, What, and When of Assessment.