<h3 align="center" style="MARGIN: auto 0cm; TEXT-ALIGN: center;"><font face="宋体">请教：样本<span lang="ZH" style="mso-fareast-language: ZH;">选择</span>性<span lang="ZH" style="mso-fareast-language: ZH;">偏差纠正</span>的方<span lang="ZH" style="mso-fareast-language: ZH;">法</span><span lang="EN-US" style="mso-fareast-language: ZH;"><p></p></span></font></h3><p style="TEXT-INDENT: 24pt; LINE-HEIGHT: 20pt; mso-char-indent-count: 2.0; mso-line-height-rule: exactly;"><font face="宋体" size="3">我在做农村劳动力转移研究，现在有一个困难，请教各位。</font></p><p style="TEXT-INDENT: 24pt; LINE-HEIGHT: 20pt; mso-char-indent-count: 2.0; mso-line-height-rule: exactly;"><font size="3"><font face="宋体">在调查时，会出现样本选择偏差（</font><span lang="EN-US" style="FONT-FAMILY: 'Times New Roman';">sample selection bias</span><font face="宋体">）问题，对这个问题，用<span lang="ZH" style="mso-fareast-language: ZH;">赫克曼</span>的二阶段法可以解决。但如何解决我不是太清楚，所以想问问这方面的高人。</font></font></p><p style="TEXT-INDENT: 24pt; LINE-HEIGHT: 20pt; mso-char-indent-count: 2.0; mso-line-height-rule: exactly;"><font size="3"><font face="宋体">另外，还想问下各位大侠</font><span lang="EN-US" style="FONT-FAMILY: 'Times New Roman';">switching regression</span><span style="mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman';"><font face="宋体">是怎么回事</font></span><span style="mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';"><font face="宋体">，我看了一篇这样的文章，想弄明白，为了说得更清楚点，我把文章上传。</font></span></font></p><p style="TEXT-INDENT: 24pt; LINE-HEIGHT: 20pt; mso-char-indent-count: 2.0; mso-line-height-rule: exactly;"><font face="宋体" size="3"><span style="mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">谢谢！</span></font></p><p style="TEXT-INDENT: 24pt; LINE-HEIGHT: 20pt; mso-char-indent-count: 2.0; mso-line-height-rule: exactly;"><font face="宋体" size="3"><span style="mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';"></span></font><span lang="EN-US" style="mso-fareast-language: ZH;"><p></p></span> </p> <br/>