i.variable

[parry madani]

Hi, may you help me please to understand when should I use i. before variable and when not?
e.g: reg health_expenditures i.round age_hh age_sp educ_hh educ_sp i.female_hh i.indigenous hhsize i.dirtfloor i.bathroom land hospital_distance if enrolled ==1
why some variables have i. and some don't? Thanks.

[Sven-Kristjan Bormann]

You can use the command

help fvvarlist

to get more information about the factor variable notation in Stata.
Usually, you specify i.variable when you want Stata to treat this variable as an indicator or categorical variable. Stata will then create on the fly the necessary dummy variables for you, so that you don't need create these dummy variables yourself.

[parry madani]

Thanks Sven-Kristjan Bormann