Forearm fractures represent one of the most common fractures in children aside from clavicle fractures, and the distal radius is the most common fracture site accounting for 20-30% of these fractures. Maintaining acceptable reduction is not always possible, and re-displacement or re-angulation is the most commonly reported complication. Factors leading to this complication can be broadly divided into three groups: fracture-, surgeon- and patient-related. The quality of casting has been historically measured subjectively. The description of several casting indices by different authors has been a major undertaking, attempting to address objective assessment of this factor. The following have been described: cast index, padding index, gap index, three point index and second metacarpal-radius angle. For distal radius fractures we think that the three point index is the most valuable measurement for predicting re-displacement among surgeon related factors; this index has not been used in forearm fractures in which the rest of the indices seem to be useful in predicting re-displacement. The casting indices should not be interpreted as a separate issue but in conjunction with fracture characteristics and patient factors.