[hend elgamiel]

you refer before to this code to convert negative value to log can use it
Code:

sign(x) * log(abs(x) + 1)

asinh(x)

sign(x) * abs(x)^(1/3)

[hend elgamiel]

my model that i use it
xtreg newinvestment smoothness overfirm smoothness*overfirm control variables fe
iwant transform newinvestment into log and use the model as follow

xtreg lognewinvestment smoothness overfirm smoothness*overfirm control variables fe. can do this after convert negative value to log can use it
Code:

sign(x) * log(abs(x) + 1)

asinh(x)

sign(x) * abs(x)^(1/3)

[Nick Cox]

Good, so you know about those transformations.

[hend elgamiel]

yes , iam not using GLM i use xtreg and i want use this formula to convert negative value to log
xtreg lognewinvestment smoothness overfirm smoothness*overfirm control variables fe. can use it or no ?

[Nick Cox]

I am sorry, but I can't see a new question in #19.

[hend elgamiel]

sorry , not a new question but i assert iam not using GLM i use xtreg . so,my question is
can use the formula to convert negative value to log with xtreg or no ? as follow
xt reg lognewinvestment smoothness overfirm smoothness*overfirm control variables fe.

[Nick Cox]

Again: yes, you can do it.

[hend elgamiel]

thank you Nick Cox