This study examined the incidence and nature of the errors made by trainee coders during their coding of question types in interviews in which children disclosed abuse. Three groups of trainees (online, postgraduate and police) studied the coding manual before practising their question coding. After this practice, participants were given two-page field transcripts to code in which children disclosed abuse. Their coding was assessed for accuracy; any errors were analysed thematically. The overall error rate was low, and police participants made the fewest errors. Analysis of the errors revealed four common misunderstandings: (1) the use of a ‘wh’ question always denotes a specific cued-recall question; (2) ‘ Tell me’ always constitutes an open-ended question; (3) open-ended questions cannot include specific detail; and (4) specific questions cannot elicit elaborate responses. An analysis of coding accuracy in the one group who were able to practise question coding over time revealed that practice was essential for trainees to maintain their accuracy. Those who did not practise decreased in coding accuracy. This research shows that trainees need more than a coding manual; they must demonstrate their understanding of question codes through practice training tasks. Misunderstandings about questions need to be elicited and corrected so that accurate codes are used in future tasks.