I have a panel data. There are three alternative proxies (i.e. IndVar1, IndVar2, IndVar3) that basically measure the same concept. I was wondering how I can use principal component analysis to somehow combine these three proxies into one proxy so that the subsequent analysis/table can be cleaner.

Main model in my research: reghdfe DepVar IndVar Controls, absorb() cluster()

See below for the data on DepVar and IndVar. I assume no control variables will be used for the principal component analysis, correct? Thank you in advance for the help!

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input long gvkey double(fyear DepVar) float IndVar1 double IndVar2 float IndVar3
12994 1992  -.56    .00540844                   .  .6532383
12994 1993  -.28   .004935834                   .  .6034814
12994 1994  -.33   .004775097                   .  .6251687
12994 1995   -.2   .004983093                   .  .6231105
12994 1996  -.15   .004461602                   .  .6325336
12994 1997  -.24   .003900709                   .  .6226345
12994 1998  -.16  .0029155216                   .   .578259
12994 1999  -.23   .003016023                   . .58972865
12994 2000   -.2  .0030279916                   . .59530157
12994 2001     .   .002729808                   .  .4891296
12994 2002  -.64  .0021383914                   . .58651394
12994 2003  -.22   .002304107  .07442265412013015  .6755146
12994 2004  -.79  .0018747656 .062054743157105366   .664766
12994 2005  -.84   .001843272 .055298161709759375   .489827
12994 2006 -1.18  .0017245542 .058979753733659865  .4455284
12994 2007  -.63  .0013577248 .043039874231813637  .4127912
12994 2008  -.11  .0022961204   .0738202692003167  .3696525
12994 2009  -.63  .0022685607  .07338793706063122  .4201931
12994 2010  -.55   .002429222  .07591318393406761  .4039361
12994 2011  -.57   .001742565  .06081552044609666  .4516295
12994 2012  -.53  .0015599926  .04406979048788129   .476481
12994 2013  -.95  .0016679754 .044451545599926624 .44745025
12994 2014  -.26  .0011239594 .025345286241558036  .5163922
12994 2015  -.22  .0009625988 .027145287003981236  .4973588
12994 2016  -.19  .0009307549  .02531653253342371 .51517814
19049 1992     .            .                   .         .
19049 1993     .            .                   .         .
19049 1994     .            .                   .         .
19049 1995     .            .                   .         .
19049 1996     .            .                   .         .
19049 1997     .            .                   .         .
19049 1998     .            .                   .         .
19049 1999     .  .0005279381                   .         .
19049 2000     .  .0004776801                   . .52466106
19049 2001     . .00044878325                   . .54433024
19049 2002     .  .0005047504                   .         .
19049 2003     .  .0006503357                   .  .6144845
19049 2004     .  .0003528647                   .         .
19049 2005     . .00033243175                   .  .4410313
19049 2006     . .00032095055                   .         .
19049 2007     . .00050686934                   .  .6006066
19049 2008     .  .0002772205                   .         .
19049 2009     . .00027057092                   .         .
19049 2010     . .00028201297                   . .54251695
19049 2011     . .00025021454                   .  .7300749
16950 1994     .            .                   .         .
16739 1992     .            .                   .         .
16739 1993     .            .                   .         .
16739 1994     .            .                   .         .
16739 1995     .            .                   .         .
16739 1996     .            .                   .         .
16739 1997     .            .                   .         .
16739 1998     .            .                   .         .
16739 1999     .  .0003397757                   .         .
 4641 1999  -.75  .0039060125  .01679585385129795  .6458617
 4641 2000  -.48     .0045971 .013331589564619169  .6057627
11908 1992   -.2   .015568634   .1712549838617809  .8920395
11908 1993  -.13   .015002538  .11551954946221668  .9201134
11908 1994  -.09   .014272025  .11274899586111282  .8750779
11908 1995  -.06    .01522486  .12788881948782013   .861227
11908 1996   -.1    .01369816  .08492859833567344  .8307174
11908 1997  -.09    .01317675  .10014329715217499  .8125359
11908 1998  -.08    .02582409  .17818623727783686  .7449759
11908 1999  -.18   .006290726 .035857137614871276  .9388587
11908 2000     .   .007939343  .03255130800682783  .8582537
13073 1992     .  .0005427379                   . .54051685
12115 1992 -1.58  .0027985075 .024067164179104476  .4264534
12115 1993 -1.89   .002607562 .021382007822685786  .6258829
12115 1994     .   .003222836  .02707182320441989  .4209149
12825 1992  -.09   .009577443   .2767881086465157  .7387033
12825 1993  -.06   .009337733   .2960061184380197  .6722038
12825 1994  -.07    .01399246  .37359869623191266  .7162285
12825 1995  -.11   .011777083   .3627341676742616  .7804794
12825 1996  -.13   .012164562  .34304065396686373   .759369
12825 1997  -.14    .01380677    .443197323110909  .7223861
12825 1998  -.12   .013886148  .42075029051283735  .6724367
12825 1999  -.12   .009612634    .290301555371118  .6642201
12825 2000   -.3    .01029577  .26974915761886936  .6841277
12825 2001  -.32   .009998227   .1909661469103205  .6845236
12825 2002  -.31   .010245856  .20081877753573799  .6544336
12825 2003  -.18   .010452835   .1604510171062917  .6696278
12825 2004   -.1    .00971764  .14965164375979684  .6465802
12825 2005   -.2   .008470789  .12452058942268873  .6323833
12825 2006  -.17   .007518207  .11765994168486289   .611187
12825 2007  -.06   .007628929  .09993896856881294  .6062316
12825 2008  -.15    .00736284  .08651337933355771  .6536069
12825 2009  -.08   .006611036  .08991008991008992  .5995871
12825 2010  -.09   .006138777  .08103186025414538 .55019194
12825 2011  -.09   .006405038   .0925528002413253 .55718964
12825 2012  -.12   .005809563   .0720385754952652  .5646573
12825 2013  -.08   .005638063 .058072047810773346  .5540121
12825 2014  -.13   .005265921  .05055284429445174 .53680456
12825 2015  -.11   .004824248  .06247401645636254  .5315951
12825 2016  -.09   .004845646  .04942558904884008  .5211627
12825 2017  -.05    .00531318                   .  .5373825
12096 1992     .    .00945335 .014180024660912454 1.0209436
12096 1993 -1.16    .01277275 .015327301756253327  .6785985
12096 1994  -.61   .009256304  .02036386849664858  .7435537
12096 1995  -.74    .00730953 .012426201855496203  .8320454
12096 1996  -.33   .004839531 .010163015792154865  .9697902
end