Children's whole number schemes can interfere with their efforts to learn fractions. To what extent do these schemes persist for secondary school students? This paper reports on the development and piloting of an interview designed to identify and probe inappropriate whole number strategies for working with fractions among secondary students. The interview showed that these strategies are still prevalent among Year 8 students. Among others who use appropriate multiplicative strategies the interview showed that some of these are still not confident in challenging instances of inappropriate whole number thinking. [Author abstract]