Classroom assessments can include a wide range of options -- from recording anecdotal notes while observing a student to administering standardized tests. The options can be roughly divided into two categories -- formative assessments and summative assessments.
  
Formative Assessment is Assessment where each learner is  assessed on continuous basis. These are mainly teacher directed or  self assessments which each individual takes on continuous basis Formative Assessments  is the use of day-to-day, often informal, assessments to explore learner’s  understanding so that the teacher can best decide how to help them to develop that understanding

Formative assessment are used to identify gap between learner’s current status and desired goal or target  to improve instructional methods and student feedback throughout the teaching and learning process. For example, if a teacher observes that some students do not grasp a concept, teacher can design a review activity or use a different instructional strategy.

Formative assessment is the means to identify the “gap” between a learner’s current status and the desired goal.  Different students will have different "gaps"

Key Elements of Formative Assessments

1. The identification by teachers & learners of learning goals, intentions or outcomes and criteria for achieving these.
2. Rich conversations between teachers & students that continually build and go deeper.
3. The provision of effective, timely feedback to enable students to advance their learning.
4. The active involvement of students in their own learning.
5. Teachers responding to identified learning needs and strengths by modifying their teaching approach(es).