楼主: liuchang1989
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[回归分析求助] 为何增加year dummy;industry dummy后样本量猛掉? [推广有奖]

11
jjjj6666 发表于 2014-2-13 05:06:41 |只看作者 |坛友微信交流群
is collapsing the year dummy into less number of categories an option?

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12
liuchang1989 发表于 2014-2-13 17:11:21 |只看作者 |坛友微信交流群
jjjj6666 发表于 2014-2-13 05:06
is collapsing the year dummy into less number of categories an option?
I've thought of that, like cutting it by the M&As waves. But in most related literature, that's not common.

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13
jjjj6666 发表于 2014-2-14 00:06:44 |只看作者 |坛友微信交流群
if that's not an option, then the model itself may have problem that many cases cannot be used for prediction of the y.

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14
liuchang1989 发表于 2014-2-14 22:51:45 |只看作者 |坛友微信交流群
jjjj6666 发表于 2014-2-14 00:06
if that's not an option, then the model itself may have problem that many cases cannot be used for p ...
it is likely, drop them is the final choice.

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15
jessiexiang_ 发表于 2014-2-19 14:22:28 |只看作者 |坛友微信交流群
liuchang1989 发表于 2014-2-2 10:39
why?
我也是这种情况啊!如何解决的呢?
太容易就不是梦想。

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