 Dear students, now we are going to learn how to identify duplicate cases in SPSS. Duplicate cases are those cases which are considered duplicates if their values match for all selected variables. Deplicate cases can occur in your data for many reasons, including data entry errors in which the same case is accidentally entered more than once, or sometimes the students try to copy paste the data to increase the sample size. What happens is that you are entering data, unintentionally one case or two or three times entered from you, or when the students are doing their projects, then they to increase their sample size, they copy and paste the cases as it is so that our sample size increases. So to see these SPSS cases, if there are exact matches, then how will we identify them? For this, we will use a duplicate case command. So for this command, you will have to right click on the data tab, so when you click here, you will see the tab of the identified duplicate case. When you right click on it, you will have a dialog box like this in which you will be asked which variables you want to match. Basically, there are 40 variables in the software that match easily. In our data set, there are 8-10 variables, so we selected them and in the first window, as shown here, we selected them. And the other, by default options, we let them stay the same way and after selecting it, we clicked on the OK button. So when you click, you will have a variable that will be your primary-last. In this case, your duplicate case is identified as 0 and your primary case is identified as 1 as you can see here that the 0 is considered as duplicate and the 1 is considered as primary case. So you can identify it like this. In the output view, you will have overall summary that how many primary cases and how many duplicate cases were in your data set. So the data set we used here was a total of 21 samples, out of which there were 15 duplicate cases and 6 were actually primary cases and original cases. So when you use this command during data cleaning, you can delete such cases that are duplicated. The unintentionally came here for some reason, some data entry, those duplicate cases are added.