Hi Statalist,

I have the panel data (state-year) and run a correlations analysis between my y and x (pwcorr y x), which shows that they are negatively correlated （significant at 1% level). However, when I run the univariate fixed effect regression (xtreg y x or xtreg y x, fe), the coefficient is significantly positive. I find it confusing because I expect them to have at least the same direction.
Besides, I get the significantly negative coefficient when I run the pooled regression (reg y x, r). Does that mean I should choose the pooled regression instead of the xtreg? Many thanks!

Best regards,
Suyi Liu