Calculating the Jones model within Excel

Hi All,

I am hoping someone has experience in calculating the Jones Model, within Excel.

I have calculated the firm parameters:

α1 - Aτ-1
α2 - ∆REVτ α3 - PPEτ

As well as accτ/Aτ-1

Where Aτ = Total Assets, ∆REV = Change in revenue, PPE = Gross property, plant and equipment and accτ = Total Accruals.

Total accruals has been defined as Net Income - Cash flow from operations.

I then regress the firm parameters against accτ/Aτ-1 to derive a residual value.

I feel i am missing something, is this literally all that needs to be done?