Definition: Timing decisions
The timing of school vacations, the ending of university sessions, the payment of company dividends, the choice of the end of a tax-year or accounting period, are all examples of decisions made by individuals or institutions that cause important seasonal effects, as these events are inclined to occur at similar times each year. They are generally deterministic, or pre-announced, and are decisions that produce very pronounce seasonal components in series such as employment rates. These timing decisions are generally not necessarily tied to any particular time in the year but by tradition have become so.
Handbook on quarterly national accounts, 1999 Edition, Eurostat, p.201