Objective: Increasingly, researchers are required to obtain active parental consent prior to surveying children and adolescents in schools. This study assessed the potential bias present in a sample of actively consented students, and in the estimates of associations between variables obtained from this sample.Methods: 3,496 students from 36 non-government metropolitan schools completed an online baseline survey in 2010 as part of the Cyber Friendly Schools Project in Perth, WA. Students with active (35%) and passive (65%) parental consent were compared on a range of variables including demographic, bullying and social-emotional outcomes. The moderating effects of consent status on associations between the bullying and other outcomes were tested.
Results:The students with active parental consent were underrepresented among those students involved in problem behaviours such as bullying others, they were also more likely to have lower prosocial scores and academic scores and live with one parent who was older than other parents.. Consent status was found to be a significant moderator of the associations between bullying victimisation and certain social-emotional variables.
Conclusions and Implications:Active only parental consent leads to biased samples and estimates of associations between outcomes of interest. Strategies to boost response rates to levels sufficient to warrant the conduct of the research are labour-intensive and costly, and the obtained samples are still likely to be biased. For low risk research, such as the completion of health surveys, rigorous active-?passive consent procedures which result in higher participation rates, lower costs and reduced burden on teachers and schools, are preferred.