Martin asked for an example of the data. A simple example is copied below with one year of annual earnings in 1990 and benefit indicators for the first six months of 1990.
input id y1990 b11990 b21990 b31990 b41990 b51990 b61990
1 100 200 300 1 0 0 0 0 0
2 200 300 400 0 0 1 0 0 0
3 300 400 500 0 0 0 0 0 1
4 400 500 600 0 0 0 1 0 0
5 500 600 700 0 1 0 0 0 0
end
Thanks,
jon
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