ARDL - A unique question

[danishussalam]

Hello All,

Let's say I estimate an ARDL model of the following type

d(emp_t) c @trend emp_t(-1) lnroad(-1) d(emp_t(-1)) d(lnroad(-1)) ,

the coefficient of emp_t(-1) was b/w -1 and 0 and also the f-stat of c(3) and c(4) was greater than the upper bound value. Now I save the residual of the above equation in a series called ECM and estimate another regression for short run relationship.

my questions: which regression should I now estimate?

1) d(emp_t) c @trend d(emp_t(-1)) d(lnroad(-1)) ecm(-1)

or

2) d(emp_t) c @trend d(emp_t) d(lnroad) ecm(-1)

Secondly , also let's say that the coefficient of ecm(-1) is not b/w -1 and 0 , can we conclude that the variables have long run relationship but they do not have any short run relationship?

Would really appreciate if you can reply at your earliest.