Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
Data on transportation costs are difficult to obtain. In the absence of good data, many researchers have turned to indirect measures of transportation costs constructed using matched partner c.i.f./f.o.b. ratios from IMF and UN data. We investigate whether these data are usable, by comparing their levels and variation to directly measured transport costs for the US and New Zealand. We find that IMF c.i.f./f.o.b. ratios are badly error‐ridden in levels, and contain no useful information for time‐series or cross‐commodity variation. However, the IMF data do appear to reveal some meaningful cross‐exporter variation that might be usefully exploited by researchers.