Makes recording data easier and more systematic. Data produced more likely to be numerical: quantitative data meaning analysing and comparing data of behaviour observed between ppts is straightforward.
These behavioural categories can be called a behaviour checklist. Before O begins, R should make sure they have as much as possible included all the ways in which target behaviour may occur in their behavioural checklist
Rs should ensure all possible forms of target behaviour are included in the checklist and that they don't over lap and be exclusive. E.g.: grinning and smiling