So how smart really is the economy?

Persons in employment are classified according to where they work, among other categories. These get quite detailed, allowing a fairly high granularity. At a higher level a standard international classification is used. Each coding contains a fairly exhaustive description of what exactly is and is not in that section.
The CSO collects data on a quarterly basis on employment, including details of where, in the above sense, people work. This gives a great picture of where we are and as it is longitudinal, where we have come from. Starting in 1998 it gives us now a 16-year picture: over the end of the tiger, through the boom, the crash and now into the nascent recovery.