Not all the information collected in forms was actually processed. As a generalisation, those questions that were easy to process (typically with closed tick box answers) were fully (100%) processed. However, some questions involved write in responses which considerably increased the time required to code and enter them. For this reason, such hard to code questions were only processed for a 10% sample of forms (see below).
Where based on tick boxes coding for data entry is relatively straightforward. However, where such questions included a write in option, these had first to be converted to numerical codes, before they could be keyed into a computer.