So, I still don't get what you mean by 'measuringuring the IMPACT of the GDP.' Yes, I am aware that we can measure the GDP of a country - and a similar tool can be used to measure the GDP of sub-national jurisdictions, especially in a federal government.

For the measurement of the country's HDI, using the GDP and other indicators, yes; the regional indicators feed into the national measurement, but the inverse is also possible.

What I also know is that impact is measured in other ways, using various macroeconomic parameters. A similar approach can be used for regional measurement and for any such jurisdiction.

The country GDP is an aggregation of its various regional state's GDP. Having this we can measure the contribution of regional GDP's to the total Country's GDP in the form of percentage share or other form. But related to the concept of impact evaluation it is difficult because the regional GDP is estimated by assuming other regions of the country as the rest of the world. So, in estimation of Regional GDP, we assume that that specific region is stands by alone in different sectors of the economy.

It all falls on the dependence of one country´s economics on the other. That was a trend before Pandemics. Now the tendency is to each country makes its own rules, despite obvious exceptions as the European Union.

Yes you can