Regression discontinuity

Regression discontinuity is an evaluation in quasi-experimental design. As we know, quasi-experimental design is different from true experimental with respect to random sample assignment. Quasi experiments need tests to determine which subjects of the population will go to which group – treatment or control group. 

Regression discontinuity is a quasi-experimental evaluation technique that is used in experiments or program that has an eligibility criteria telling who from the population can participate and who cannot. This eligibility is called a cut-off point in an experiment. Regression discontinuity, also known as regression discontinuity design helps the researchers to check people for their eligibility by evaluating them below or above the cut-off point. 

Example: Marks of students can be from 0 to 100. Teacher decides to assign students that have a poor performance to a special course which will enhance their skills. So the group of students who will take the course will be put to a treatment group and those who have decent scores will not go through any treatment, hence they are called control group. 

RDD can be used to measure the outcomes of the students and decide which students are above the decided cut-off and below the cut-off.