Most secondary education students use the WWW as their only information source for class assignments. The way they search and evaluate information is not ideal (MaKinster, Beghetto, & Plucker, 2002; Walraven, Brand-Gruwel & Boshuizen, 2009). Teachers recognize the need for instruction in these skills, but instruction is still rare. Possible explanations are poor information skills of teachers themselves and lack of insight in students’ skills, since measuring information skills is often done outside educational context. A quick and easy measurement in educational practice could be a first start to 1) improve teachers’ own skills and 2) integrate information skills in the curriculum. The design and validation of such an instrument was central in this study. Based on the model of Brand-Gruwel, Wopereis and Walraven (2009), the instrument combines the advantages of off- and on-task measurements of information skills. After content validity and usability tests, 100 secondary education students went through the instrument. Their actions in the instrument were compared to their answers to the validated information skills questionnaire by Timmers and Glas (2010). Data have been gathered and analyses are currently being performed.