Table 1.

Summary of the research methods used for data collection and their relations

Method	Usefulness	Relation to other methods
On-line survey	Gathering of data from a wide audience in many countries	Provision of the information to be statistically processed
Non-probability sampling method I (convenience sampling)	Quick and extensive reach to research networks, especially when participants are under crisis situation	Rapid access to initial sample
Non-probability sampling method II (snow ball)	Extend sample to relevant participants within sample networks	Extend sample within networks
Dissemination via web links, networks and mailing lists sampling	Extend sample to relevant participants beyond sample networks	Extend sample beyond sample