Summative Assessment

Summative Assessment takes place at the end of a semester or an academic year. It is typically conducted for the purpose of grading and promotion of students to the higher classes. Its main function is to measure the overall academic achievements of students at the end of a specified period of time. Usually, degrees/certificates are awarded as a result of this assessment. Data collected through summative assessment can also be used for evaluation purposes. Curriculum developer and policy maker use this data for evaluating the effectiveness of various educational   courses or programs. Exams conducted at the end of a semester or an academic year are the main forms of summative assessment. They are either administered by the concerned educational institutions, by the state/district education boards or by some third party organizations like National Testing Services etc. Normally standardized tests are used for this type of assessment.
Summative Assessment
I hope the following simple rule may help you great in understanding the difference between formative and summative assessments.
  “If an assessment is carried out by a teacher for the purpose of getting feedback about the on-going instruction, then it is formative assessment, but if it is conducted for the purpose of grading, then it is summative assessment."
Besides summative assessment there are two other famous types of assessments which are given as under:
Diagnostic Assessment
Formative Assessment