When people are introduced into the processing chain, they become the slowest link but also the key link. They are required to intervene when automated processing and procedures cannot determine whether a given behavior is correct or not. They control the system by applying their experience and intelligence. They need accurate and relevant information to make the best decision as quickly as possible. Data traceability is therefore essential. Timestamping of data at source can be used to clearly establish the sequence of events. A brief log of measurements taken will provide a better understanding of how the system has changed in a given time period.