Definition
What is event log?
An event log is a table of process steps in which every row records one thing that happened to one case: a case identifier, the activity performed and the time it occurred, optionally with the person or system responsible. It is the minimum input required to reconstruct how a process actually ran.
Updated 4 September 2026
Why it matters
- Almost every business system already produces one, even when no analysis is done with it.
- The quality of the case identifier — an order or invoice number that survives across systems — decides whether a cross-system process can be reconstructed at all.
- It makes a baseline reproducible, so later claims about improvement can be checked.
Business example
A clinic joins appointment, billing and messaging records on the patient case reference and finds that most rescheduling effort is triggered by a single confirmation step that runs too late.
Common misconceptions
- 'We do not have event logs.' You almost certainly do; they are simply spread across systems and unnamed.
- 'It needs to include everything.' Three columns for one process are enough to start.
- 'User columns are always required.' They add insight and add data-protection obligations; aggregate where possible.
Related concepts
- Process mining
- Conformance checking
- Process intelligence
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