Comparison of cost estimates for standard and Electronic Data Capture (EDC) methods.

*Salary costs per correctly entered field were calculated according to the formulas which are presented in the methods section. The time a data supervisor (standard method) or a data manager (EDC) would need for the synchronization of the data bases and the performance of range and consistency checks was assumed to be 5 min/questionnaire. Duration of double entry of the data of one record was calculated by multiplying the median duration for one entry by two. The values for the interview duration and error rates for the standard and EDC methods were taken from the last week of the study. The costs for netbook and tablet PC are presented as relative percent increase/decrease compared to the standard method.**The duration of the interviews using EDC was longer compared to the standard paper-based method. The number of interviews per fieldworker and working day might therefore be reduced with EDC compared to the standard method. The costs for transportation might increase consequently.