Boys with official police contacts admit delinquent activities; while youngsters from Morocco and Turkey were much more reticent about admitting delinquent activities than those born in The Netherlands or coming from Surinam. These differences in willingness to admit delinquent behavior are related to social control variables, the number of police contacts, and knowledge of the Dutch language. A problem for etiological research reports that variables which are considered a cause of delinquency are also related to the tendency to admit involvement in criminality. Overall, arrest data probably provide the best information for comparing criminal involvement between ethnic groups. 21 references, 2 tables, and 2 appendix. (Author abstract modified)