Hi everyone, I have a time series data where there are several variables given.For example, disappearance of beef, pork, turkey and chicken and their retail prices (retail prices of beef...chicken), their cpi (cpi_beef...cpi_chicken), population, disposable income and overall CPI. I calculated expenditure share by the following command:
gen expmeat= cpiturkey+ cpichicken+ cpibeef+ cpiporkfresh
gen wbeef= cpibeef/ expmeat
gen wpork= cpiporkfresh / expmeat
gen wchicken= cpichicken / expmeat
gen wturkey= cpiturkey / expmeat
Is it alright?
Now, I am trying to estimate LA-AIDS model in stata. So far, I have got two commands: aidsills and quaids from internet sources but none of them provide me with how to calculate LA-AIDS (I might be wrong and missing something here). My questions are:
1. How do I calculate the stone price index which is required for LA-AIDS? I calculated expenditure share (wi), but I am not sure how to calculate stone price index from these data. I know it is lnp= sum(wi*lnpi), so here we have got wi, but what is lnpi? should it be retail price or CPI? For example, stone price index=w(beef)*cpi_beef+...+w(chicken)*cpi_chicken or is it stone price index=w(beef)*retail_beef+...+w(chicken)*retail_ch icken?
2. What is the command for LA-AIDS in stata? I think in general AIDS, we use nlsur but for LA-AIDS, we use seemingly unrelated regression (SUR). But I am not sure how to run LAAIDS. For example, how do I fit homogeneity, symmetry conditions in SUR? in aidsills command and qaids, we can impose homogeneity, symmetry conditions with the commands themselves. But not sure how to do it with SUR?
gen expmeat= cpiturkey+ cpichicken+ cpibeef+ cpiporkfresh
gen wbeef= cpibeef/ expmeat
gen wpork= cpiporkfresh / expmeat
gen wchicken= cpichicken / expmeat
gen wturkey= cpiturkey / expmeat
Is it alright?
Now, I am trying to estimate LA-AIDS model in stata. So far, I have got two commands: aidsills and quaids from internet sources but none of them provide me with how to calculate LA-AIDS (I might be wrong and missing something here). My questions are:
1. How do I calculate the stone price index which is required for LA-AIDS? I calculated expenditure share (wi), but I am not sure how to calculate stone price index from these data. I know it is lnp= sum(wi*lnpi), so here we have got wi, but what is lnpi? should it be retail price or CPI? For example, stone price index=w(beef)*cpi_beef+...+w(chicken)*cpi_chicken or is it stone price index=w(beef)*retail_beef+...+w(chicken)*retail_ch icken?
2. What is the command for LA-AIDS in stata? I think in general AIDS, we use nlsur but for LA-AIDS, we use seemingly unrelated regression (SUR). But I am not sure how to run LAAIDS. For example, how do I fit homogeneity, symmetry conditions in SUR? in aidsills command and qaids, we can impose homogeneity, symmetry conditions with the commands themselves. But not sure how to do it with SUR?
