Birthyear

[Olivia Emma]

Hi

I have a variable firstbirth_cmc how I can get the birthyear from this like 1980 etc

firthbirth_cmc
1147
1153
1322
1149
1100
1301


dataex

* Example generated by -dataex-. For more info, type help dataex
clear
input float firthbirth_cmc
1147
1153
1322
1149
1100
1301
   .
1268
1081
1103
1384
1310
1194
1153
1289
1014
1099
1199
1346
1273
   .
   .
1371
1258
1181
   .
   .
   .
1245
   .
   .
1235
1172
1314
1284
   .
   .
1385
1349
   .
1220
   .
1323
1317
   .
1097
1166
   .
1248
1381
1330
   .
1263
1162
1031
1203
1156
   .
1233
1107
1099
   .
   .
1243
   .
1225
1250
1261
   .
1262
1293
1341
1316
1264
1369
1230
1341
1276
1328
1304
   .
   .
1085
1206
   .
   .
1385
   .
1273
1241
1315
   .
1239
1363
1317
1282
   .
1326
   .
1255
end

----------

[Clyde Schechter]

* Example generated by -dataex-. For more info, type help dataex
clear
input int firthbirth_cmc
1147
1153
1322
1149
1100
1301
end

gen mdate = tm(1899m12) + firthbirth_cmc
format mdate %tm
gen birthyear = year(dofm(mdate))

[Olivia Emma]

thanks

but how you pickup this number 1899m12

[Nick Cox]

https://demographicestimation.iussp....ry-month-codes

This extended example and alternative method may help:

clear
input int firthbirth_cmc
1147
1153
1322
1149
1100
1301
-1
0
1
1486 
end

gen mdate = tm(1899m12) + firthbirth_cmc
format mdate %tm
gen birthyear = year(dofm(mdate))

gen BY = 1899 + ceil(firthbirth_cmc/12)

list 

    +--------------------------------------+
     | firthb~c     mdate   birthy~r     BY |
     |--------------------------------------|
  1. |     1147    1995m7       1995   1995 |
  2. |     1153    1996m1       1996   1996 |
  3. |     1322    2010m2       2010   2010 |
  4. |     1149    1995m9       1995   1995 |
  5. |     1100    1991m8       1991   1991 |
     |--------------------------------------|
  6. |     1301    2008m5       2008   2008 |
  7. |       -1   1899m11       1899   1899 |
  8. |        0   1899m12       1899   1899 |
  9. |        1    1900m1       1900   1900 |
 10. |     1486   2023m10       2023   2023 |
     +--------------------------------------+