Coding Question

["Roberts, J. Kyle" <jkrobert@bcm.tmc.edu>]

I have a dataset in which I need to dummy code (sort of) two separate variables.

 

Variable 1

I have 5 years of data on students in teachers classrooms.  Each teacher entered the intervention at different times (years 1-6).  I need to code a date variable for each student as zero for each student in the classroom before the intervention, and as a "1" when the intervention started.

For example, in this case, the variable "new.var" would be created from "year" and "int.year".

teach  stud   year  int.year  new.var

1        1      1        3        0

1        2      1        3        0

1        3      2        3        0

1        4      2        3        0

1        5      3        3        1

1        6      3        3        1

1        7      4        3        1

1        8      4        3        1

 

Variable 2

This is like the above data, but I need the new.var.2 variable to begin counting up from the intervention year.  For example:

teach  stud   year  int.year  new.var.2

1        1      1        3        0

1        2      1        3        0

1        3      2        3        0

1        4      2        3        0

1        5      3        3        1

1        6      3        3        1

1        7      4        3        2

1        8      4        3        2

 

Thanks,

Kyle

 

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J. Kyle Roberts, Ph.D.

Baylor College of Medicine

Center for Educational Outreach

One Baylor Plaza, MS:  BCM411

Houston, TX   77030-3411

713-798-6672 - 713-798-8201 Fax

jkrobert@bcm.edu

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