A concern existed as to whether web-based surveys produced the same data as paper-based surveys. In reviewing studies that attempted to address this concern over validity, Danscombe (2006) cited a study by McCabe (2004) in which 7,000 university students in the United States were surveyed regarding illicit drug use. The participants were randomly assigned to either a web-based or postal-based survey group and identical instruments were administered using the two delivery modes. McCabe (2004) found that the two modes produced similar results. Danscombe (2006) also reviewed a study by Lozar and Vehovar (2002) in which 400 primary and secondary school students in Slovenia were randomly placed into two groups, one group received a web survey and the other received a printed questionnaire through the mail. The researchers found “…no major differences in substantive responses” (p. 149).