'invalid name' error in logit MLE program

[Matthew Chapman]

If anyone can help it would be great. I'm trying to do a logistic MLE. I've written an ado with the log-likelihood function, but it keeps giving me an 'invalid name' error. Here's my program:



program mylogit_lf
version 15.0
args lnf xb
quietly replace 'lnf' = ln(invlogit( 'xb')) if $ML_y1 == 1
quietly replace 'lnf' = ln(invlogit(-'xb')) if $ML_y1 == 0
end



Here's the error after ml check:




------------------------------------------------------------------------------
-> mylogit_lf __000008 __000009
- `begin'
= capture noisily version 15: mylogit_lf __000008 __000009
---------------------------------------------------------------------------- begin mylogit_lf ---
- version 15.0
- args lnf xb
- quietly replace 'lnf' = ln(invlogit( 'xb')) if $ML_y1 == 1
= quietly replace 'lnf' = ln(invlogit( 'xb')) if FO_label == 1
' invalid name
------------------------------------------------------------------------------ end mylogit_lf ---
- `end'
= set trace off
------------------------------------------------------------------------------


I've tried with another more complicated program using the args -> tempvar -> gen double -> replace format, but this gives me the same error.


Some one please help?

[William Lisowski]

Welcome to Statalist.

You've apparently advanced all the way to writing programs without having first mastered local macros. You should read Chapter 18 Programming of the Stata User's Guide PDF included in your Stata installation and accessible through the Stata Help menu, paying particular attention to section 18.3 Macros.

Because the Stata User's Guide PDF is printed in a typeface that does not display punctuation identically to Stata, note that where the PDF has something that looks like

 ‘shortcut’ 

you need to type on your keyboard

 `shortcut'

where the first character is (on an American English keyboard) the "left single quote" beneath the tilde (~) character below the ESC key, and the final character is the usual "single quote" ("apostrophe") just to the left of the RETURN key.

In your code this will be

program mylogit_lf
version 15.0
args lnf xb
quietly replace `lnf' = ln(invlogit( `xb')) if $ML_y1 == 1
quietly replace `lnf' = ln(invlogit(-`xb')) if $ML_y1 == 0
end