Hi, I am struggling to find what the differences between the two is. It looks as as if there is a huge overlap between the two. I know one is produced for a student and one for an Actuary, but still most of the content is the same.
I guess the difference is subtle. As with any communication try to put yourself in the shoes of the user. Someone reviewing the entire exercise may read both in depth, but A student picking up the calculations where you left off, extending it, etc may focus on the audit trail. Senior actuary/clients will focus on the summary, so it should have results and enough information for user to have confidence in results eg data, method and assumptions, but not too much detail as to distract from the message. Clearly a general overview of the method and assumptions belongs in both. Audit trail user wants to know what is being done. Summary user wants to have overview of approach and assumptions to place results in context (if there is an obvious flaw in the approach or assumptions they'll discount the results. Uncertainty in assumptions/approach translates to uncertainty in results.) Anything spread sheet specific, eg layout, any limitations of calculations specific to spread sheet (eg only certain things parameterised), etc belong in audit trail only. Can user use audit trail to quickly familiarise themselves with the spread sheet without examining majority of cells? Results (and comments thereon) probably fit best in summary only. Reasonableness checks could be put in both. I'm inclined to include in audit trail only, but it may not be wrong to include a couple of higher level checks in summary to help user gain confidence in results.
An audit trail is written in a way so that someone who takes up the work from you should be able to understand step by step what you've done, how you've done it and where you've done it. The focus is on the process and the controls to understand and reproduce your work. The summary is a report to the reviewing actuary/boss which summaries what you've done and why you've done it. It doesn't dwell on trivialities but concentrates more on the big picture and the results.
