/*****************************
 * National Health Insurance *
 * Author(s): Comfort Sumida *
 *****************************/

/****************************************************************************
 * Product: Age profiles of NHI                                             *
 * Data requirements: Individual data on health usage, data on NHI benefits *
 *    dayshosp = # of days hospitalized (individual)                        *
 *    outpatn = # outpatient visits (individual)                            *
 *    tx940 = household NHI benefits                                        *
 *    tx94 = individual NHI benefits (only available for those aged 14+     *
 * Methodology: Regression method with prices as a cubic in age             *
 ****************************************************************************/

/****************************************************************************
 * note(s): - do-files are for all years (loops)                            *
 *          - estimated age profiles are not adjusted to aggregate controls *
 ****************************************************************************/

/* NHI */
/* adding cubic and dummy for age 0 */

# delimit ;
set more off;

forval i = 1995(1)2003 {;
log using "C:\testquad4 `i'", replace;

/* merging individual and household data sets */
use "C:\mind`i'.dta", clear;
sort savehhid;
save "C:\temp1.dta", replace;

use "C:\hhitem`i'.dta", clear;
sort savehhid;
merge savehhid using "C:\temp1.dta";
save "C:\testquad4 `i'.dta", replace;

/* unallocated portion of NHI */
sort savehhid;
by savehhid: egen nhi = sum(tx94);
gen health1 = tx940 - nhi;

/* generating usage variables */
by savehhid: egen hosp1 = sum(dayshosp);
by savehhid: egen out1 = sum(outpatn);
by savehhid: egen ahosp = sum(age*dayshosp);
by savehhid: egen aout = sum(age*outpatn);
gen agesq = age^2;
by savehhid: egen a2hosp = sum(agesq*dayshosp);
by savehhid: egen a2out = sum(agesq*outpatn);
gen age3 = age^3;
by savehhid: egen a3hosp = sum(age3*dayshosp);
by savehhid: egen a3out = sum(age3*outpatn);
gen age0 = age == 0;
by savehhid: egen a0hosp = sum(age0*dayshosp);
by savehhid: egen a0out = sum(age0*outpatn);

reg health1 hosp1 out1 ahosp aout a2hosp a2out a3hosp a3out a0hosp a0out [w = mult2] if rel == 1, robust noconstant;
gen a0 = _b[hosp1];
gen b0 = _b[out1];
gen a1 = _b[ahosp];
gen b1 = _b[aout];
gen a2 = _b[a2hosp];
gen b2 = _b[a2out];
gen z0 = _b[a3hosp];
gen z1 = _b[a3out];
gen x0 = _b[a0hosp];
gen x1 = _b[a0out];

/* estimated outpatient and inpatient expenditures */
gen inpatient = (a0 + a1 * age + a2 * agesq + z0 * age3 + x0 * age0) * dayshosp;
gen outpatient = (b0 + b1 * age + b2 * agesq + z1 * age3 + x1 * age0) * outpatn;
recode inpatient outpatient (. = 0);

sort savehhid;
egen sum = rsum(inpatient outpatient);
by savehhid: egen total1 = sum(sum);
gen share1 = sum/total1;
gen health3 = share1 * health1;
recode health3 (. = 0);

lowess inpatient1 age, bwidth(0.1) nograph gen(sinpatient1);
lowess outpatient1 age, bwidth(0.1) nograph gen(soutpatient1);
egen smooth1 = rsum(sinpatient1 soutpatient1);

/* total NHI expenditure is allocated portion + individual reported */
recode tx94 (. = 0);
egen health4 = rsum(health3 tx94);
lowess tx94 age1, bwidth(0.1) nograph gen(stx94);
egen health5 = rsum(smooth1 stx94);

save "C:\testquad4 `i'.dta", replace;

log close;
};