Direct costs mean costs that a library incurs to fill an ILL borrowing or lending request.
Fill rate refers to the percentage of borrowing or lending requests successfully filled.
The factor of time is measured in the number of calendar days it takes to complete a borrowing request. This is why there is a questionnaire on general characteristics of the library. The libraries can use it to check the level of service compared with other libraries. The study is a survey in two parts. The first part is a questionnaire concerning general characteristics of the library and on the costs of ILL activities.