Systematic collection of valid reliable data
It is essential that all information contributing to an incident is collected and analysed.
Time invested at this stage could save a lot of time later on. It could prevent missing something that could lead to the true root cause.
Amount of data can be vast.
Collecting information can take a considerable amount of time and effort. The person responsible for carrying out RCA, or team leader if one is appointed, should judge if the information collected is sufficient and provides adequate evidence to assess the problem.
Careful planning should be undertaken to maximise the resources used, such as costs and time.