two fpfit plots on one with estopts

[Pakeezah Saadat]

Hello stata-users,
I have tried plotting two fpfit curves on one graph using

twoway (fpfit var1 var2) (fpfit var1 var2)

which worked perfectly fine. For fractional polynomial fitting, it automatically assigns a degree but I wanted to increase the polynomial degree so I used the code

twoway fpfit var1 var2, estopts(degree(3))

with varying degrees. But now that I am trying to put the two graphs together, it tells me that "option estopts() not allowed".
Does anyone know why that might be happening?

[Nick Cox]

What code is it that produces the error? This is fairly silly substantively, but it is syntax that works:

. sysuse auto, clear
(1978 Automobile Data)

. twoway (fpfit mpg weight if foreign, estopts(degree(3))) (fpfit mpg weight if !foreign, estopts(degree(2)))

[Pakeezah Saadat]

To put estopts() with both fpfit commands looked redundant to me so I was using

 twoway (fpfit var1 var2)(fpfit var1 var2), estopts(degree(3))

.

Your code works. I guess I just need to play around a little more to see how things fit. Thanks.

[Nick Cox]

That syntax of yours would imply that estopts is an option of twoway, and it is not. You placed the option call outside the fpfit parentheses.