Skip to main content

Currently Skimming:

3 Panel Findings and Conclusions: Data Quality and Reliability
Pages 15-19

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 15...
... The panel concurs with the BTS report that available freight data are not of sufficient coverage and quality to permit precise determination of international trade traffic by state. The panel's review of the availability of validated data to support estimates suggests needed improvements in data collection programs to enhance the accuracy and reliability of international trade traffic measures for formula apportionment purposes.
From page 16...
... The primary measures used in the current allocation formulas include lane miles, vehicle miles traveled, diesel fuel data, state population, urbanized area population, and nonhighway recreational fuel use. Each of these data elements has its own error measures, as well as an established validation procedure that is documented in guidelines that were carefully developed in a federal-state cooperative venture.
From page 17...
... We offer two examples, on disaggregating diesel fuel use and on computing substate estimates. 1 By errors due to data sources here, we mean all sources by which the estimate fails to equal the true value, which includes various types of bias and sample variance.
From page 18...
... The report finds that the regression relationships for many states are weak, suggesting that "diesel fuel usage estimates do not provide good predictors of total trade ton-miles on a state-by-state basis." The panel is concerned that the next step -- to break down the weak total relationships into domestic and international components -- would require comparing estimates of international trade traffic ton-miles from the BTS study with estimates of total ton-miles by state from other sources. The panel concurs with the BTS report that the process of disaggregating diesel fuel use into its domestic and international trade traffic components would compound variability in that it would apply a ratio of two estimates with significant variability with state diesel fuel use data that have known quality problems.
From page 19...
... . The issue of the quality of data used to support fund allocation formula programs is a complicated one; for a broad review of the considerations involved and much more general issues concerning inputs to and use of fund allocation programs, see National Research Council (2003b)


This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More information on Chapter Skim is available.