This part of ISO 13215 specifies a method to predict and quantify misuse of child restraint systems which is called Misuse Mode and Effect Analysis (MMEA). Such misuse may degrade the performance of child restraint systems. As a predictive method it should be applied at an early stage, before the child restraint system is put into use by consumers. The MMEA method is recommended to be used by manufacturers of child restraint systems. However, in order to further minimize misuse of child restraint systems, this method may also be used for type approval purposes. Being predictive implies the possibility of incompleteness and errors. Such errors can be minimized, if the proposed method is supported by the panel method [1] and by field studies. This part of ISO 13215 represents the best present consensus, but should be reviewed more frequently than other International Standards and revised in the light of increasing experience.