As the title suggested, I would like to count the number of the students who had grade retention in K-12 system. For example, I want to know how many students who made normal grade progression, how many students who had one-time grade retention, how many students who had two-time grade retentions....etc. The dataset is structured in long format below,
*Simulated dataset.
clear
input byte (id grade)
1 1
1 2
1 2
1 3
1 4
1 4
1 4
1 4
1 5
1 6
1 6
2 1
2 2
2 3
2 4
2 4
2 5
2 5
2 6
2 6
2 6
2 7
3 1
3 2
3 3
3 4
3 5
3 6
3 7
4 1
4 1
4 2
4 3
4 4
4 5
4 6
5 1
5 2
5 3
5 4
5 5
5 5
6 1
6 2
6 3
6 4
6 4
6 5
7 1
7 2
7 3
7 3
7 5
7 6
7 7
end
​​​​​​​Thank you for your help!