Dear Everyone,

I'm new here and I would like to measure willingness to pay by using double bounded method analysis. I have found the constant and coefficients for each independent variables but I've got a message of 'not found' for my variable, is it because of the mistake in my command:

nlcom (wtp_b[_cons]+Emplo_m*b[Emplo]+Income_m*b[Income]+TriedtoQuit_m*b[TriedtoQuit]+Heal_Res_m*b[Heal_Res]+PeerInfluence_m*b[PeerInfluence]+Toquit_m*b[Toquit]+Notice_m*b[Notice])), noheader

I have seven independent variables and this is what I received:
Emplo_m not found
r(111);

Thanks for your kind assistance.