Hi everyone,

I am new to this forum and I'm hoping that someone can help me. I have a sample of firms with secondary listings for which I have data for the years before and after the cross-listing (i.e. in the example below for variable "YEAR", -1 stands for the year before the listing, +1 stands for the year after the listing). I am trying to make a new variable which includes matched-adjusted measures based on control firms that best reflect the cross-listed firms based on pre-listing characteristics at "YEAR" -1. The control firms that I need to match to the cross-listed firms should, at the time of "YEAR" -1 (i.e. prelisting), have the same first two digits of the SIC code, should be in the same home country, and should have total assets of between 80%-120% of the cross-listed firms. The fiscal year ends also need to be similar.

So for example, there is 1 firm that cross-listed in year 2001, and there are 5 firms that meet the characteristics as described above in year 2000. For year 2001 and thereafter, I want to know their mean ROA in order to calculate the difference between the cross-listed firm and similar non-cross-listed firms. Thus, I want to know their mean ROA in 2001, in 2002, in 2003, etc.

I would be really grateful if anyone could tell me how I could solve this. Thank you very much in advance!

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input float(id fy_end) str16 home_country float(list_dt YEAR) str16 host_country int SIC double assets float ROA
 1 13148 "UNITED STATES" 14620 -5 "GERMANY" 3443   54342          .
 1 13514 "UNITED STATES" 14620 -4 "GERMANY" 3443   64816          .
 1 13879 "UNITED STATES" 14620 -3 "GERMANY" 3443   84052  .04358016
 1 14244 "UNITED STATES" 14620 -2 "GERMANY" 3443  116790  .06372121
 1 14609 "UNITED STATES" 14620 -1 "GERMANY" 3443  178392  .08801964
 1 14975 "UNITED STATES" 14620  0 "GERMANY" 3443  279960  .11109801
 1 15340 "UNITED STATES" 14620  1 "GERMANY" 3443  376506  .10770877
 1 15705 "UNITED STATES" 14620  2 "GERMANY" 3443  460890  .09567142
 1 16070 "UNITED STATES" 14620  3 "GERMANY" 3443  515080  .08723305
 1 16436 "UNITED STATES" 14620  4 "GERMANY" 3443  592146   .0926562
 1 16801 "UNITED STATES" 14620  5 "GERMANY" 3443  704957    .107686
 1 17166 "UNITED STATES" 14620  6 "GERMANY" 3443  900030   .1105852
 1 17531 "UNITED STATES" 14620  7 "GERMANY" 3443 1028851  .10546523
 1 17897 "UNITED STATES" 14620  8 "GERMANY" 3443 1798857  .07963835
 1 18262 "UNITED STATES" 14620  9 "GERMANY" 3443 1754039  .06654527
 1 18627 "UNITED STATES" 14620 10 "GERMANY" 3443 1716317  .05474105
 1 18992 "UNITED STATES" 14620 11 "GERMANY" 3443 1708051  .05764289
 1 19358 "UNITED STATES" 14620 12 "GERMANY" 3443 1727560  .05893978
 1 19723 "UNITED STATES" 14620 13 "GERMANY" 3443 1677374 .064430475
 1 20088 "UNITED STATES" 14620 14 "GERMANY" 3443 2103174  .04909151
 1 20453 "UNITED STATES" 14620 15 "GERMANY" 3443 1979222  .06290856
 1 20819 "UNITED STATES" 14620 16 "GERMANY" 3443 2004894  .05941611
 1 21184 "UNITED STATES" 14620 17 "GERMANY" 3443 2073407  .05437331
 1 21549 "UNITED STATES" 14620 18 "GERMANY" 3443 2005064  .06965812
 4 13148 "UNITED STATES"     .  . ""        2086 3418716  .06788923
 4 13514 "UNITED STATES"     .  . ""        2086 4780748  .05249178
 4 13879 "UNITED STATES"     .  . ""        2086 6094975  .05417676
 4 14244 "UNITED STATES"     .  . ""        2086 5165892  .06159072
 4 14609 "UNITED STATES"     .  . ""        2086 5693226  .04699972
 4 14975 "UNITED STATES"     .  . ""        2086 4872353  .05373235
 4 15340 "UNITED STATES"     .  . ""        2086 3228608  .05093681
 4 15705 "UNITED STATES"     .  . ""        2086 3316627   .0506786
 4 16070 "UNITED STATES"     .  . ""        2086 4326118  .05055572
 4 16436 "UNITED STATES"     .  . ""        2086 4589734  .06068325
 4 16801 "UNITED STATES"     .  . ""        2086 3848592  .07949453
 4 17166 "UNITED STATES"     .  . ""        2086 4251210  .08920801
 4 17531 "UNITED STATES"     .  . ""        2086 4066916   .1211793
 4 17897 "UNITED STATES"     .  . ""        2086 3504467  .15714344
 4 18262 "UNITED STATES"     .  . ""        2086 4999753  .12179302
 4 18627 "UNITED STATES"     .  . ""        2086 5389783  .14254451
 4 18992 "UNITED STATES"     .  . ""        2086 6164592  .14513743
 4 19358 "UNITED STATES"     .  . ""        2086 6987519  .13453545
 4 19723 "UNITED STATES"     .  . ""        2086 5895089 .065596804
 4 20088 "UNITED STATES"     .  . ""        2086 4934456  .09805194
 4 20453 "UNITED STATES"     .  . ""        2086 4852534   .1068788
 4 20819 "UNITED STATES"     .  . ""        2086 4670643  .09908614
 4 21184 "UNITED STATES"     .  . ""        2086 4724564  .11761403
 4 21549 "UNITED STATES"     .  . ""        2086 4352829  .11175652
 5 20635 "CANADA"        20919 -1 "GERMANY" 7812    2831  -2.854115
 5 21000 "CANADA"        20919  0 "GERMANY" 7812    4873 -1.4005746
 5 21365 "CANADA"        20919  1 "GERMANY" 7812    5301 -1.3310696
 6 13879 "UNITED STATES" 15384 -5 "GERMANY" 8741   52562  .03439747
 6 14244 "UNITED STATES" 15384 -4 "GERMANY" 8741   40445 .028582025
 6 14609 "UNITED STATES" 15384 -3 "GERMANY" 8741   43150 .035874855
 6 14975 "UNITED STATES" 15384 -2 "GERMANY" 8741   39842  .02010441
 6 15340 "UNITED STATES" 15384 -1 "GERMANY" 8741   34408 -.09462915
 6 15705 "UNITED STATES" 15384  0 "GERMANY" 8741   28139 -.01012829
 6 16070 "UNITED STATES" 15384  1 "GERMANY" 8741   20656  .04875097
 7 13330 "UNITED STATES" 15029 -5 "GERMANY" 2836   11392  -.5019312
 7 13695 "UNITED STATES" 15029 -4 "GERMANY" 2836    4207  -1.848348
 7 14060 "UNITED STATES" 15029 -3 "GERMANY" 2836    2133 -1.0656352
 7 14425 "UNITED STATES" 15029 -2 "GERMANY" 2836     249 -15.016065
 7 14791 "UNITED STATES" 15029 -1 "GERMANY" 2836    8683   -.377289
 7 15156 "UNITED STATES" 15029  0 "GERMANY" 2836   11458   .0899808
 7 15521 "UNITED STATES" 15029  1 "GERMANY" 2836    7665  -.6067841
 7 15886 "UNITED STATES" 15029  2 "GERMANY" 2836    4813  -.5879909
 7 16252 "UNITED STATES" 15029  3 "GERMANY" 2836   21384 -.11284138
 7 16617 "UNITED STATES" 15029  4 "GERMANY" 2836   17470  -.7624499
 7 16982 "UNITED STATES" 15029  5 "GERMANY" 2836   22499  -.7305658
 7 17347 "UNITED STATES" 15029  6 "GERMANY" 2836   10921 -1.4285322
 7 17713 "UNITED STATES" 15029  7 "GERMANY" 2836   43187   -.386621
 7 18078 "UNITED STATES" 15029  8 "GERMANY" 2836   24660  .14939173
 7 18443 "UNITED STATES" 15029  9 "GERMANY" 2836    2580          .
 8 18262 "UNITED STATES" 20045 -5 "MEXICO"  1422 3239283   .0554064
 8 18627 "UNITED STATES" 20045 -4 "MEXICO"  1422 3074743  .06158824
 8 18992 "UNITED STATES" 20045 -3 "MEXICO"  1422 3147822   .0579102
 8 19358 "UNITED STATES" 20045 -2 "MEXICO"  1422 3160926  .04943583
 8 19723 "UNITED STATES" 20045 -1 "MEXICO"  1422 3259826  .06560657
 8 20088 "UNITED STATES" 20045  0 "MEXICO"  1422 7464392   .0473066
 8 20453 "UNITED STATES" 20045  1 "MEXICO"  1422 6961732  .07008026
 8 20819 "UNITED STATES" 20045  2 "MEXICO"  1422 7300905  .09053138
 8 21184 "UNITED STATES" 20045  3 "MEXICO"  1422 8992511   .0788455
 8 21549 "UNITED STATES" 20045  4 "MEXICO"  1422 9551419   .0718242
 9 13179 "UNITED STATES" 15316 -5 "GERMANY" 3552   47751   .2413143
 9 13545 "UNITED STATES" 15316 -4 "GERMANY" 3552   83625  .18593723
 9 13910 "UNITED STATES" 15316 -3 "GERMANY" 3552  114539  .13377976
 9 14275 "UNITED STATES" 15316 -2 "GERMANY" 3552  106302 .014684577
 9 14640 "UNITED STATES" 15316 -1 "GERMANY" 3552   21346  -.4457978
 9 15006 "UNITED STATES" 15316  0 "GERMANY" 3552   54030  -.1588932
 9 15371 "UNITED STATES" 15316  1 "GERMANY" 3552   38279 -.29023746
 9 15736 "UNITED STATES" 15316  2 "GERMANY" 3552   36002 -.06505194
 9 16101 "UNITED STATES" 15316  3 "GERMANY" 3552   30346 -.11062413
 9 16465 "UNITED STATES" 15316  4 "GERMANY" 3552   26626   -.067866
 9 16829 "UNITED STATES" 15316  5 "GERMANY" 3552   26354  .02917963
 9 17166 "UNITED STATES" 15316  5 "GERMANY" 3552   27188  .08573636
 9 17531 "UNITED STATES" 15316  6 "GERMANY" 3552   29300  .06484642
 9 17897 "UNITED STATES" 15316  7 "GERMANY" 3552   21030 -.29448408
11 13875 "UNITED STATES" 15652 -5 "GERMANY" 5200  223370  .10552894
11 14239 "UNITED STATES" 15652 -4 "GERMANY" 5200  263223  .10850876
11 14610 "UNITED STATES" 15652 -2 "GERMANY" 5200  301631   .1167486
end
format %tddd/nn/CCYY fy_end
format %tddd/nn/CCYY LD2
label var id "group(DSCD)"
label var fy_end "date of fiscal year end"
label var home_country "Country of home market"
label var list_dt "cross-listing date"
label var host_country "country of first cross-listings"
label var SIC "sic code"
label var assets "total assets"