Coverage with evidence development

Nevertheless, there is limited evidence about how the approach can work in practice, and the evidence available comes from international examples applying only a few elements of the VBP approach. The situation is made additionally complex because VBP metrics are often used on conjunction with other schemes. Sweden combines VBP with other approaches such as coverage with evidence development (CED) schemes (Cochrane et al., 2015), and this in turn makes gathering evidence on the effectiveness of VBP approaches challenging (Persson, 2012). 

The data disclosed by Vannice are highly valuable, as they allow a comparison on turnover basis. With the evidence now available regarding the development of extensive overlayers of surface carbon during FT synthesis (cf. Section IV), we would recommend that any forthcoming interpretation of the overall kinetics takes explicity into account the variations in surface-carbon coverage with both the reaction conditions and the nature of the transition metal. Beeck 30 already pointed out that carbon deposition may well depend on the morphology of the surface, a point substantiated in more recent surface studies (57). This may underlie the large support effects disclosed in one of Vannice s more recent kinetic studies (52). 

Evidence development schemes (34 schemes in use, regrouped into coverage-with-study or coverage-with-appropriateness determination approaches)... 

In the first treatment of this problem, taking up ideas from molecular crystal work, Hammaker et al. considered only the direct interaction between the dipoles. Mahan and Lucas made a substantial improvement by taking into account both the contribution from the images and the electronic polarizability of the molecules. Still they were not able to explain the observed coverage dependent freqency shifts. The reason for this became evident when Persson et al. developed a new theory for the dipole-dipole interaction based on the old ideas but with several important new concepts. They showed... 

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