请问xtheckmanfe返回r(2000)说没有样本是为什么?我想用二阶段选择模型,perf是因变量,intensity是自变量,firmage、firmsize是控制变量,tag是选择变量,z是排他约束变量。代码如下,一直返回r(2000),不明白在使用xtheckman或xtheckmanfe命令之前要注意点什么?数据有什么问题吗?
xtset id year
xtheckmanfe perf intensity firmage firmsize, select (tag=z)
* Example generated by -dataex-. To install: ssc install dataex
clear
input long id double(z perf tag) int year double(firmage intensity firmsize)
2001 7 .22353 1 2010 140 .004739286445108797 22.540234070904507 .003097863332042473 2.6923076923076925
2001 8 .175119 1 2011 152 .004593954002692953 22.69057593128697 .003097863332042473 2.6923076923076925
2001 1 .113459 1 2012 164 .0038292788898201826 22.781876400587493 .003097863332042473 2.6923076923076925
2001 1 .107635 1 2013 176 .0035822660988528185 22.86988397073096 .003097863332042473 2.6923076923076925
2001 2 .091409 1 2014 188 .003665088659552693 22.93414828812555 .003097863332042473 2.6923076923076925
2001 3 .041366 1 2015 200 .00315525097861933 22.99788978314982 .003097863332042473 2.6923076923076925
2001 4 .11596 1 2016 212 .0029688866482026417 23.157789824666416 .003097863332042473 2.6923076923076925
2001 1 .115824 1 2017 224 .002814913387075014 23.623742741506536 .003097863332042473 2.6923076923076925
2001 1 .154467 1 2018 236 .0028333855016148 23.811344291581776 .003097863332042473 2.6923076923076925
2001 2 .086309 1 2019 248 .0023334296706579638 24.073223351035534 .003097863332042473 2.6923076923076925
2001 3 .119999 1 2020 260 .002154658414238238 24.15392518119496 .003097863332042473 2.6923076923076925
2001 1 .13235 1 2021 272 .001906602622494966 24.26977970912199 .003097863332042473 2.6923076923076925
2001 1 .09969 1 2022 284 .0016952219976217517 24.3678700794763 .003097863332042473 2.6923076923076925
2002 2 .007957 1 2012 142 .00019493414028623558 19.523544486071227 .00009447533584775139 2.7
2002 3 .054034 1 2013 154 .00003909230829257888 22.67608402296915 .00009447533584775139 2.7
2002 4 .041308 1 2014 166 .000026681209449845455 23.00043258673139 .00009447533584775139 2.7
2002 5 .050495 1 2015 178 .00021990354880569286 23.17697951043624 .00009447533584775139 2.7
2002 1 .066164 1 2016 190 .0002529897500338219 23.26785420618319 .00009447533584775139 2.7
2002 2 .074839 1 2017 202 .00011321137610640157 23.386154771389823 .00009447533584775139 2.7
2002 1 .042974 1 2018 214 .00004014589212455361 23.372411139747214 .00009447533584775139 2.7
2002 2 .040719 1 2019 226 .00002254868513257738 23.545099518289778 .00009447533584775139 2.7
2002 3 .047258 1 2020 238 .00002473692242422315 23.608442262203813 .00009447533584775139 2.7
2002 4 .047836 1 2021 250 .00001050952582158352 23.60669229696358 .00009447533584775139 2.7
2003 7 .161231 1 2010 124 .001025631015144379 21.30872200766641 .0011032771524989362 2.6923076923076925
2003 8 .097714 1 2011 136 .0010482305954570836 21.55954624350905 .0011032771524989362 2.6923076923076925
2003 1 .073368 1 2012 148 .0011486169006467656 21.595315943853166 .0011032771524989362 2.6923076923076925
2003 1 .094791 1 2013 160 .0011478282822851087 21.45208412669073 .0011032771524989362 2.6923076923076925
2003 2 .111511 1 2014 172 .001218335939147718 21.479901269551256 .0011032771524989362 2.6923076923076925
2003 3 .115981 1 2015 184 .0011691329356655238 21.490180695173976 .0011032771524989362 2.6923076923076925
2003 4 .129878 1 2016 196 .0012573384547082092 21.70709484784466 .0011032771524989362 2.6923076923076925
2003 1 .143264 1 2017 208 .0010646532716946972 21.832768360088508 .0011032771524989362 2.6923076923076925
2003 1 .105354 1 2018 220 .0009692541160561837 21.877869432160747 .0011032771524989362 2.6923076923076925
2003 2 .085232 1 2019 232 .0010953359674267605 21.96878554522258 .0011032771524989362 2.6923076923076925
2003 3 .114911 1 2020 244 .0009954070407378484 21.947853918094143 .0011032771524989362 2.6923076923076925
2003 1 .119696 1 2021 256 .0010576352978743807 22.11927187920727 .0011032771524989362 2.6923076923076925
2003 1 .110554 1 2022 268 .0011452031656415118 22.286275894918457 .0011032771524989362 2.6923076923076925
2004 2 .111193 1 2011 123 .002049977686877939 22.155821389843393 .0027333678629818154 3.1818181818181817
2004 3 .073343 1 2012 135 .004792993669499417 22.501982205609615 .0027333678629818154 3.1818181818181817
2004 4 .046719 1 2013 147 .004486248568608199 22.757662415039487 .0027333678629818154 3.1818181818181817
2004 5 .04186 1 2014 159 .00407187735433832 23.330990824059253 .0027333678629818154 3.1818181818181817
2004 6 .039474 1 2015 171 .0031136005316710793 23.70441211267252 .0027333678629818154 3.1818181818181817
2004 7 .027843 1 2016 183 .00271983245786582 23.91077003145357 .0027333678629818154 3.1818181818181817
2004 1 .022269 1 2017 195 .0024372652556582572 24.093661571591603 .0027333678629818154 3.1818181818181817
2004 . .029375 1 2018 207 .0020410980173573585 24.002352154630856 . .
2004 1 .034981 1 2019 219 .0017074401762895268 24.005544516349666 .0027333678629818154 3.1818181818181817
2004 2 .032627 1 2020 231 .0015314043258273457 24.063513261096837 .0027333678629818154 3.1818181818181817
2004 3 .031747 1 2021 243 .0015505938454831562 24.12594301485216 .0027333678629818154 3.1818181818181817
2004 1 .037518 1 2022 255 .0016058126206809147 24.125276331287168 .0027333678629818154 3.1818181818181817
2005 7 .052503 1 2010 175 .00445327856060331 22.343877196029425 .0025685031751696602 3.5384615384615383
2005 8 .06509 1 2011 187 .0035941779265191045 22.63591203445971 .0025685031751696602 3.5384615384615383
2005 1 .019917 1 2012 199 .0031172835468012993 22.942794667812784 .0025685031751696602 3.5384615384615383
2005 2 .00046 1 2013 211 .0018922630158538728 23.113831907122027 .0025685031751696602 3.5384615384615383
2005 3 .001121 1 2014 223 .0025814853018767047 23.28327993825183 .0025685031751696602 3.5384615384615383
2005 4 .001072 1 2015 235 .002699131309903065 23.32086406659042 .0025685031751696602 3.5384615384615383
2005 5 .002065 1 2016 247 .0024024794450891117 23.32815302804046 .0025685031751696602 3.5384615384615383
2005 1 -.070297 1 2017 259 .0019234358432976058 23.3582888382418 .0025685031751696602 3.5384615384615383
2005 2 -.332437 1 2018 271 .0017666881100935584 23.069064538471267 .0025685031751696602 3.5384615384615383
2005 3 .039292 1 2019 283 .0019028157011707358 22.409495817856378 .0025685031751696602 3.5384615384615383
2005 4 -.12734 1 2020 295 .0023207728814676276 22.125306562511753 .0025685031751696602 3.5384615384615383
2005 5 -.142867 1 2021 307 .0025731298201124614 21.955829258918097 .0025685031751696602 3.5384615384615383
2005 1 -.121755 1 2022 319 .0021635998144171236 21.708690896919126 .0025685031751696602 3.5384615384615383
2006 7 .06338 1 2010 123 .0014765062183209263 21.262527673217843 .0004330990177076952 2.6923076923076925
2006 8 .178597 1 2011 135 .0002179456395093362 21.714894360236475 .0004330990177076952 2.6923076923076925
2006 1 -.082687 1 2012 147 .0009119323590580759 21.51634371589586 .0004330990177076952 2.6923076923076925
2006 1 -.096136 1 2013 159 .0006181045305771001 21.423291327924062 .0004330990177076952 2.6923076923076925
2006 2 .005224 1 2014 171 .0004244002340058177 21.23385943569268 .0004330990177076952 2.6923076923076925
2006 3 .008681 1 2015 183 .000388774292211267 21.16902611842894 .0004330990177076952 2.6923076923076925
2006 4 .03614 1 2016 195 .00016373158521888151 21.205112491359213 .0004330990177076952 2.6923076923076925
2006 1 .055353 1 2017 207 .00040867342774908466 21.30114580474695 .0004330990177076952 2.6923076923076925
2006 1 .00361 1 2018 219 .0002330153955053213 21.377122768696726 .0004330990177076952 2.6923076923076925
2006 2 -.06729 1 2019 231 .00030283467857162243 21.26407819441705 .0004330990177076952 2.6923076923076925
2006 3 .021294 1 2020 243 .00027227296938366844 21.451290266475755 .0004330990177076952 2.6923076923076925
2006 1 .045153 1 2021 255 .000055663366781567695 21.64427918405766 .0004330990177076952 2.6923076923076925
2006 1 .117257 1 2022 267 .000156432533307369 21.67398459535417 .0004330990177076952 2.6923076923076925
2007 2 . 0 2010 225 . 21.669443675595346 . .
2007 3 . 0 2011 237 . 21.729374014081866 . .
2007 4 . 0 2012 249 . 21.809359248874053 . .
2007 5 . 0 2013 261 . 22.016160076040894 . .
2007 1 . 0 2014 273 . 22.0502445905598 . .
2007 2 . 0 2015 285 . 22.114919182260582 . .
2007 3 . 0 2016 297 . 22.260232697331904 . .
2007 1 . 0 2017 309 . 22.3756315030569 . .
2007 2 . 0 2018 321 . 22.593998661520704 . .
2007 3 . 0 2019 333 . 22.749200846664575 . .
2007 1 . 0 2020 345 . 23.02970719814636 . .
2007 2 . 0 2021 357 . 23.168845653109553 . .
2007 1 . 0 2022 369 . 23.41389626881185 . .
2008 7 .091475 1 2010 111 .0008403897587430839 22.417272736732006 .0005405041571028868 3.5384615384615383
2008 8 .1086 1 2011 123 .0006041968812674388 22.526167803479417 .0005405041571028868 3.5384615384615383
2008 1 .100909 1 2012 135 .000621203963418724 22.600197777176152 .0005405041571028868 3.5384615384615383
2008 2 .087155 1 2013 147 .000827585749751817 22.616035147504014 .0005405041571028868 3.5384615384615383
2008 3 .103606 1 2014 159 .0006053853782988563 22.696810226773028 .0005405041571028868 3.5384615384615383
2008 4 .101007 1 2015 171 .0005832592943138742 22.74909805754187 .0005405041571028868 3.5384615384615383
2008 5 .084043 1 2016 183 .000601301643678302 23.06213240935597 .0005405041571028868 3.5384615384615383
2008 1 .139811 1 2017 195 .00037293838539188503 23.36965130378285 .0005405041571028868 3.5384615384615383
2008 2 .104401 1 2018 207 .0005287152870835403 23.66480677719805 .0005405041571028868 3.5384615384615383
2008 3 .033432 1 2019 219 .00042902307210292286 23.607696390254542 .0005405041571028868 3.5384615384615383
2008 4 .050639 1 2020 231 .0005035833669674399 23.784100044920116 .0005405041571028868 3.5384615384615383
2008 5 .085734 1 2021 243 .00024911119788471534 24.0257678367282 .0005405041571028868 3.5384615384615383
2008 1 .043382 1 2022 255 .0002598600634349288 24.186248827328463 .0005405041571028868 3.5384615384615383
end
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