(The reason that the number of records from the using (payroll) data that were not matched is zero is because I specified option keep(master match), meaning I discarded the unmatched payroll records. Of those, 174,528 matched, which is 98.7 percent. merge 1:1 personid date using payroll, keep(master match) In any case, I receive the data, and here is what happened when I merged the data with my sample: They might be records from follow-up visits of a medical experiment. Let’s call this second set of data the payroll data, although if I can imagine fictional conversations, you can imagine the data are something else. It’s just random stuff,” he replied, knowing how well I respond to the word random. “How many?” I asked Bob from data processing during a fictional conversation, my paranoia kicking in.

I’ve been told that most of my 737 people should be in this second dataset, but I’ve been warned that, due to data collection or data processing errors over the years, a small fraction will not be found. It has over 3,000 people in it and it covers a longer stretch of time. The second dataset contains additional information (variables) on the sample of interest. Overall, my dataset has 176,880 observations. For each person, I have data recorded on the first and fifteenth of every month, from year 2000 to 2009. The first, sample.dta, is the one of analytic interest to me. Just to fix ideas, let’s assume I have two datasets. In this dataset we have repeated observations on persons and, within person, the observations can be uniquely identified by the calendar date.

In panel or longitudinal datasets, there are multiple observations on each person or thing and to uniquely identify the observations, we need at least two key variables, such as In that discussion, each observation in the dataset could be uniquely identified on the basis of a single variable. In Merging data, part 1, I discussed single-key merges such as Multiple-key merges arise when more than one variable is required to uniquely identify the observations in your data.

How to merge and center in excel 2011