When my husband and I have extra money left over at the end of the month, we move it to the Household Stock Portfolio. We look for stocks we believe are overlooked, undervalued, and cheap (emphasis on cheap!). With modern technology, I can define an action to buy or sell a specific stock at a specific price for a defined time period. The purchase or sale of the stock occurs without human intervention; this is an example of a "temporal event."

A temporal event is a "…process based exclusively on timing criterion." Business processes often include temporal events which do not require any human interaction but are based on business rules identifying the timing criteria. It important for a Business Analyst (BA) to understand what a temporal event is and how to gather temporal event business rules.

Temporal events have business rules governing when the event begins, what the time interval is, and when the event ends. There may be sub-tasks related to the temporal event that also need to be captured. For example, the stock limit order may start on the first business day of the month and continue until fourteen business days have passed. A sub-task process may generate a notification to the user three business days prior to the start of the limit order, notifying the user the limit order is about to go into effect.

Because the business rules are based on time, temporal events can be a challenge to model. Consider a manufacturing environment where the business rule is to start the next task "soon as possible" or "late as possible" based on another task. Notice I did not say previous task, because temporal events can occur in parallel with other actions. In my experience, the most difficult temporal event to understand and document is one that does not execute sequentially but spawns multiple concurrent temporal events, each with different rules and interacting with different stakeholders. Using our stock limit order example, if the stock price of a manufacturer of wooden pallets falls, the limit order purchases the pallet manufacturer stock but also checks the prices of trucking, railroad, and transoceanic stocks and sells based on rules defined for each industry.

A temporal event can be repeated, or it could be a unique, "one off" incident. Take care not to confuse a rare temporal event occurrence with a spontaneous event. A spontaneous event is "an event based on some condition(s) becoming true, but not based on any timing criteria." An example of a spontaneous event would be the stock market halts trading; this event occurs because of the action of falling stock prices, not because of timing rules. The stock market halt is a spontaneous event; when the market returns to trading and the price falls sufficiently, my limit order purchases the stock as a temporal event.

In the words of Carson Wentz,

"Timing and accuracy are really what matters at the end of the day."

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