  The design of a publisher's electronic interface can have a measurable effect
on electronic journal usage statistics. A study of journal usage from six
COUNTER-compliant publishers at thirty-two research institutions in the United
States, the United Kingdom and Sweden indicates that the ratio of PDF to HTML
views is not consistent across publisher interfaces, even after controlling for
differences in publisher content. The number of fulltext downloads may be
artificially inflated when publishers require users to view HTML versions
before accessing PDF versions or when linking mechanisms, such as CrossRef,
direct users to the full text, rather than the abstract, of each article. These
results suggest that usage reports from COUNTER-compliant publishers are not
directly comparable in their current form. One solution may be to modify
publisher numbers with adjustment factors deemed to be representative of the
benefit or disadvantage due to its interface. Standardization of some interface
and linking protocols may obviate these differences and allow for more accurate
cross-publisher comparisons.
