MSA Comparison continued
There is increasing interest in service exports, which many believe to be America's comparative advantage in trade. The government does not compile service exports at the regional level, but Brookings has estimated them. For six of Tennessee's metro areas, service exports account for basically a quarter or more of all exports. Note the high correlation between the intensity of service exporting with the overall level of exporting for a metro area.
The two sets of metro export data starkly illustrate how difficult it is to obtain accurate export data. Take a look at the differences in the two sets of numbers. For a few areas, such as the Nashville metro area, they are relatively close; for others they are quite far apart. What's going on? Government data is largely taken from Shipper's Declaration Forms (augmented by other sources for NAFTA).
The forms provide lots of detailed information but suffer from some problems. If the form is filled out incorrectly, the data taken is obviously going to be incorrect. If the form is filled out by company headquarters, listing the HQ rather than the branch plant as the export location, that's a problem. If the form is filled out by a broker, freight forwarder, or some other agent who is unsure of the location of the export, is aggregating exports from different places, or is simply a bit lazy and filling in the agent's address, that is going to be a problem, too.
The general thinking is that these errors bias exports toward port areas, where most form filling is going on. In the case of Tennessee, that would tend to bias the allocation of exports toward Memphis, and you can see the much larger export figure for Memphis exports in the Census Bureau numbers than in the Brookings numbers.
Many analysts attempt to get around this issue by estimating exports based on where productive activity is located. If a community produces 10% of America's fabricated metals, then it should also produce 10% of America's fabricated metal exports, and so forth. This sounds reasonable, but it might also be misleading. Companies matter: some are export powerhouses; others are not. Take Kingsport-Bristol: the Brookings export estimate, based on production, is much lower than the information taken from Shipper's Declaration Forms. What's going on there? What's going on is Eastman Chemical, one of America's largest and most competitive exporters. The Brookings number is almost certainly too low because it isn't able to take the competitiveness of Eastman Chemical into account in compiling its estimates.
These export differences become less acute at higher levels of aggregation. Tennessee-level exports turn out roughly the same no matter how they are estimated, but as one drills down, the problem gets larger. A truly accurate picture of metro exporting involves triangulating across different export numbers to get a feel for what's going on.
The good news is no matter who is doing the accounting, the past five years have looked pretty good for most of the state's metro areas, in particular its larger communities.