贸易引力模型中控制变量总被drop掉怎么处理？比如是否共同语言、共同宗教这类01变量？

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收藏 2019-04-14

我跑的是 xtreg lny lngdp lnpop distw comlang comrelig fta eu

但是结果总是

distw |       0  (omitted)
   comlang |       0  (omitted)
comrelig |       0  (omitted)
      fta |       0  (omitted)
      eu |       0  (omitted)
原因是：
note: comlang omitted because of collinearity
note: comrelig omitted because of collinearity
note: fta omitted because of collinearity
note: eu omitted because of collinearity

距离是有系数的，只有控制变量会被omitted掉

是我数据不对还是模型不对呢？
如果被drop掉的都是不显著的那模型意义就不大呀？而且我看别人的论文中也是如此跑出来的，实在不解，还请大家为我解惑呀~感激不尽

下面是数据表<

ISO3_O	cty_code	year	lny	distw	lnpop	lngdp	comrelig	comlang	fta	eu
AUS	6021	2004	22.86301291	14802.03194	8.681589919	57.27999911	0.191275999	1	0	0
AUS	6021	2005	22.9745485	14802.03194	8.704004992	57.46793656	0.191275999	1	1	0
AUS	6021	2006	23.12280045	14802.03194	8.728399835	57.59933868	0.191275999	1	1	0
AUS	6021	2007	23.19754693	14802.03194	8.744157133	57.77616619	0.191275999	1	1	0
AUS	6021	2008	23.31253946	14802.03194	8.773656031	58.00472499	0.191275999	1	1	0
AUS	6021	2009	23.10005247	14802.03194	8.803032917	57.85399303	0.191275999	1	1	0
AUS	6021	2010	23.25835331	14802.03194	8.82688352	58.099856	0.191275999	1	1	0
AUS	6021	2011	23.55125203	14802.03194	8.848043112	58.33194813	0.191275999	1	1	0
AUS	6021	2012	23.7402892	14802.03194	8.872407864	58.47293565	0.191275999	1	1	0
AUS	6021	2013	23.48065314	14802.03194	8.89731923	58.52644502	0.191275999	1	1	0
AUS	6021	2014	23.49111618	14802.03194	8.920371828	58.49289883	0.191275999	1	1	0
AUS	6021	2015	23.4597465	14802.03194	8.941639104	58.44647589	0.191275999	1	1	0
BRA	3510	2004	22.83382706	8088.513876	10.89449953	57.35976464	0.280847996	0	0	0
BRA	3510	2005	22.94796863	8088.513876	10.91523704	57.70882073	0.280847996	0	0	0
BRA	3510	2006	23.18069449	8088.513876	10.93552366	57.97593682	0.280847996	0	0	0
BRA	3510	2007	23.40480572	8088.513876	10.95488625	58.24713468	0.280847996	0	0	0
BRA	3510	2008	23.6527907	8088.513876	10.97361035	58.45405366	0.280847996	0	0	0
BRA	3510	2009	23.47137942	8088.513876	10.99133381	58.41311045	0.280847996	0	0	0
BRA	3510	2010	23.66956399	8088.513876	11.00847341	58.72995465	0.280847996	0	0	0
BRA	3510	2011	23.7971889	8088.513876	11.02453872	58.91096139	0.280847996	0	0	0
BRA	3510	2012	23.84297925	8088.513876	11.04056543	58.85516751	0.280847996	0	0	0
BRA	3510	2013	23.79841128	8088.513876	11.05627522	58.89052578	0.280847996	0	0	0
BRA	3510	2014	23.70086733	8088.513876	11.09315504	59.00066227	0.280847996	0	0	0
BRA	3510	2015	23.48703898	8088.513876	11.10954982	58.72809331	0.280847996	0	0	0