 Students, now we are going to study the regression discontinuity designs in quasi-experimental designs. Regression discontinuity design which is also referred as RDD is invented in 1960 by Threstvoid and Campbell. RDD is an impact evaluation method used to evaluate programs that have a cut-off point determining who is eligible to participate. RDD allows researchers to compare the people immediately above and below the cut-off point to identify the impact of the program on a given outcome. If we see the diagram design of regression discontinuity design, then you can see that you have two groups, one is called control group and the other is called treatment group. The variable we have is a continuous index, a measure of which we can compute a continuous index value, such as your GPA test score, poverty score, age, and a clearly defined cut-off point. For example, when we talk about Amphil and Ph.D. programs, the requirement for them is three GPAs. So, this is a cut-off point that only those can enroll in the Amphil and Ph.D. program who scored more than three GPAs or three GPAs. So, those who score less than this do not fulfill the requirement. If I give you another example, like the poverty index, you recently saw that the government is giving income support to poor people. So, for their determination, a poverty index is developed in which those people who are below the index, we offer them income support. What is its assumption? Its assumption is that all persons on one side of the cut-off are assigned to one group and all persons on the other side of the cut-off are assigned to the other group. For example, if this is a cut-off point, then one group on one side is lower value and the other group on the other side is higher value. So, the null hypothesis is that there is no difference on the basis of the cut-off in the scores of the people. So, there is no difference on the basis of the cut-off. If we talk about its alternate hypothesis, then it will be that there is the effect of the treatment on the basis of the cut-off value. If your first score was here, then the score in the control group will be here. So, those who are poor, what is their trust in the government? It is here and those who are not poor, their trust in the government is here. So, this difference is called discontinuity, which can come because of treatment in this design.