One of the macro economic indicator that is monitored by organizations is "the contribution of construction to the GDP". This is measured in terms of percentage contribution of construction.
My question is:
What does this comprise? Does it include large infrastructure projects/oil refineries/nuclear plats etc or not?
As you probably have seen already, you can find the measure of value added to GDP per sector of the US economy at the Bureau of Economic Analysis website, specifically at this web address: https://www.bea.gov/industry/iedguide.htm
On the GDPbyInd_VA_NAICS file downloadable on the website, you can find the calculations for the value added by industry and sector as well as the definitions of each sector used to compile the national accounts.
According to that file, Construction includes all firms classified with a NAICS code 23. Now, if you go to NAICS definitions on the U.S. Census Bureau Website you can see the breakdown of what subsectors are included. There you can also click on the details for each subsector. For example, for 237130 Power and Communication Line and Related Structures Construction, you can find as an illustrative example, “Nuclear power plant construction.”