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7.28. To collect information concerning mode 4, compilers should consider adding a specific question in a household survey about the reason for the trip (“business trip”). In combination with the “self-employed” sociodemographic characteristic, that question can be used as a basis. If such a survey is conducted as a telephone sample, compilers should be aware that self-employed persons are difficult to reach and therefore they should also consider using a specific sample of mobile phone numbers or use a web-based survey.
Next: D.3. Household surveys and mode 2 and mode 4 number of persons/trips