Rules
Part of How SLA deadline calculators determine due dates
SLA deadline clocks: what your contract must say about calendars and closures
SLA deadline clocks depend on contract terms: which calendar is named and versioned, rest days, substitution, mid-term changes, and what to store per clock.
No closure dates appear on this page. An agreement that points at a list on a page like this one has adopted a list with no publisher, no issue date and nobody answerable for it, which is the opposite of what an agreement is for.
What follows is what the contract text has to settle, because a service level clock cannot be computed until it does.
What to take away
- The agreement has to name a calendar, not describe one. A named, published, versioned list is the only kind that can be checked two years later.
- Say who may change the list during the term and what happens to clocks already running when they do.
- A closure that shortens a day is not a closure that removes one, and only an hours-based clock can tell the difference.
What the text has to settle
Whose calendar. The provider's, the customer's, or a named third party's. Each gives a different answer, and a provider operating in one region for a customer in another will otherwise apply its own without saying so.
Which list, by name and version. A reference to a publisher and a publication is checkable. A reference to "public holidays" is not, because several lists in the same country answer to that description and they close different days.
Rest days. A Saturday and Sunday week is a default, not a term. Where a party operates on a different week the difference is roughly one day a week, larger than any closure list.
Substitution. Whether a closure falling at a weekend is observed on a working day instead. This changes the deduction in some years and not others, so a term that is silent will look consistent for a year or two and then diverge.
The clock's unit. Open days, business hours against a stated window, or elapsed time. These give very different answers for the same span: a request arriving late on a Friday afternoon and answered on the Monday morning is 68 elapsed hours and four business hours against a nine to five window.
Who may change the list, and when it takes effect. This is the term most often missing, and the one that matters after the first year.
Mid-term changes
A published list gains entries. A closure announced weeks ahead cannot have been in a list issued a year earlier, and a running clock has to do something about it.
Mid-term list change rules
Pin at term start
- Running clock
- No change
- Best for
- Predictability
- Risk
- Stale list
Pin at clock start
- Running clock
- Keeps old list
- Best for
- Work in flight
- Risk
- Mixed versions
Always current list
- Running clock
- Moves
- Best for
- Actual practice
- Risk
- Surprise shifts
Three arrangements, each defensible:
Effect on a running clock
- Pin the version at the start of the term
- No change until renewal
- Pin at the moment each clock starts
- Clocks started earlier keep the old list
- Always use the current list
- Running clocks move
Suits
- Pin the version at the start of the term
- Predictability
- Pin at the moment each clock starts
- Fairness to work in flight
- Always use the current list
- Matching what actually happens
Any of these is workable. What is not workable is having no rule, because the parties then discover their disagreement in the one case where a deadline was missed. Whichever is chosen, record the version each clock was computed against, the same discipline software versioning applies to anything consumers pin to.
Where the underlying days come from
The days themselves generally come from an enacting instrument rather than from custom, which is what makes the list auditable. In the United States the federal set is codified in statute at 5 U.S.C. 6103. Reading the instrument, rather than a convenient summary, is what tells you whether substitution applies and who may add a day.
Procedural rules can govern counting when a deadline is legal, not contractual, and the federal civil rules set their own method in Rule 6 on computing and extending time. Where that rule applies, it beats the ticketing system.
Contracts sometimes adopt such a rule by reference, which cleanly settles several questions above at once.
Partial days
A day that closes early is not a closure and not half a day. At day resolution it has no representation at all, so an agreement whose clock counts open days simply cannot express it, and one whose clock counts business hours can.
Day vs hour clocks
Open-day clock
- Partial day
- Cannot express
- Needs per-date windows
- No
- Resolution
- Whole days
Business-hour clock
- Partial day
- Can express
- Needs per-date windows
- Yes
- Resolution
- Hours
If partial days matter, the clock has to be in hours and the schedule has to carry per-date windows. That machinery is under working hours, and the closure list's own versioning is under how closure calendars are made.
What to store per clock
The calendar identifier and version, the rest-day set, the window, the unit, and the segments the clock passed through. That is enough for either party to reproduce the number without asking the other for anything.
A stored due moment on its own is not enough, because it cannot be recomputed and cannot be defended. The three-state model those segments come from is under service level deadlines, and the walking arithmetic that produces a due moment from a budget is under the deadline formula.
Common questions
Why will this page not list 2027 closures for a service agreement?
Because the governing calendar is a term of the agreement, not a fact about the year. A list here would be right for a few readers and quietly wrong for the rest.
Is it acceptable for the provider's calendar to govern?
It is common and it is defensible, provided it is stated. What causes trouble is a provider applying its own calendar under a term that says nothing.
What happens when a closure is announced after a clock has started?
Whatever the agreement says. If it says nothing, the parties will disagree, and the disagreement will surface on the one clock that mattered.
Should the agreement list the dates rather than name a publisher?
Listing dates fixes them for the term, which is predictable and goes stale. Naming a publisher and a version keeps the list current and needs a rule about mid-term changes. Either works; only one of them can be done without a rule.
