/******************************************************************
Scale ID: 			STAI
Scale Name: 		State Anxiety Inventory
TILDA Variables: 	COGstai6_total; COGstai6_equiv20
Dataset:      		TILDA Wave 1-6
Author:       		
Institution:  		The Irish Longitudinal Study on Ageing (TILDA)

Description:
Generates scoring for the Penn State Worry Questionnaire.

Version:      1.0
Date:         2026-09-01
Language:     Stata

******************************************************************/

* Raw 6-item total score
egen COGstai6_total = rowtotal( ///
    COGstateanxiety1 ///
    COGstateanxiety2 ///
    COGstateanxiety3 ///
    COGstateanxiety4 ///
    COGstateanxiety5 ///
    COGstateanxiety6 ///
)

* Require all six items to be answered
egen COGstai6_missing = rowmiss( ///
    COGstateanxiety1 ///
    COGstateanxiety2 ///
    COGstateanxiety3 ///
    COGstateanxiety4 ///
    COGstateanxiety5 ///
    COGstateanxiety6 ///
)

replace COGstai6_total = . if COGstai6_missing > 0

label variable COGstai6_total ///
    "STAI-6 state anxiety total score (6-24)"


* 20-item equivalent score
gen COGstai6_equiv20 = COGstai6_total * (20/6)

label variable COGstai6_equiv20 ///
    "STAI-6 state anxiety score, 20-item equivalent (20-80)"


* Checks
summarize COGstai6_total COGstai6_equiv20
tab COGstai6_total, missing


* Drop temporary variable
drop COGstai6_missing