Some countries have laws or standards that specify calling hours allowed for unsolicited calls of any type and these should be observed for surveys via mobile phones as well. Mobile phone numbers rarely indicate the respondent’s location and therefore the researcher should anticipate that the person being contacted might be in a different time zone, and thus verify the convenience of the time, location and situation. In the absence of such requirements, researchers should observe the same calling hours as for
fixed-line phone surveys. For surveys in the business-to-business sector, acceptable times are implicit in the office hours of the business concerned. Similar attention should be paid to the sending of SMS text messages to mobile phones to avoid the participant receiving the message received alert outside “normal hours”.