Limitations to this analysis include the use of data collected using mixed modes with comparisons based on data collected by telephone and self completion.
A final aspect of data quality that was measured included a comparison of completeness of data collected via the two modes of administration.
Types of data collected include information on the purpose, mode, transit time, trip length, and other related aspects of daily trips taken within a 24-hour period.
There may be some effect from different modes of data collecting (interview versus survey), although this effect is likely modest, as described for above.
Similarly, approaches that integrate modes of data collection within a study or synthesise data collected by varying modes across studies are only addressed in passing.
The national registries of Finland, Norway, and Sweden are different with regard to organization, collected variables, and modes of data collection.
Quantitative data will be collected through questionnaires and GPS and accelerometer devices (see section titled "Quantitative data collection" for more details on these modes of data collection).
Data are typically collected via telephone or face-to-face; however, no study has statistically investigated whether the questionnaires' items operate equivalently across these modes of data collection.
62.6% of surveys were collected in-person; 37.4% via mail, with no difference in overall satisfaction by mode of data collection (p = 0.3).
Collecting representative data on sensitive issues, especially data that are used to determine population prevalence estimates, is problematic whatever mode of data collection is employed [ 2- 6].
