Count backwards from the date, including the part nobody counts

A buyer wants the report by the 31st of December next year. Fifteen months from today. A twelve-month period. There is no version of this that is tight.

Count it anyway, backwards, and include the two stretches that are not the period. One of them belongs to the reviewer and one of them belongs to whoever has not finished the controls, and neither of them appears on the plan with the deadline on it.

Predict

Fifteen months until the report is wanted. A twelve-month observation period, six weeks of reviewer fieldwork after it closes, eight weeks of work that must land before it opens. When does work have to begin?

Choose one answer

Around the middle of next year — there are three spare monthsIn about seven weeks, when the period opensIt had to begin eight days agoIt depends on the reviewer, so there is no date

Lock in answer

Window countdown

≈ Hypothetical model, not a forecast

Works backwards from a target report date to the day the observation window must already have opened, and the day work must have started for it to open on time. It answers when you must start, and it will never answer whether you are ready — no arrangement of dates can tell you that.

It assumes

• Today is a declared input rather than the system clock, so the answer is reproducible.
• Fieldwork happens after the period closes and before the report is issued.
• Preparatory work finishes before the period opens, because it is not evidence of operation otherwise.
• Window length is calendar months, so its length in days depends on which months it covers.
• Weekends, holidays and release freezes are counted as ordinary working days.
• Nothing here says whether the controls work or whether anybody is ready; it is a calendar.

It ignores

• Whether the controls work, whether evidence exists, or whether anybody is ready — this is a calendar, and a date cannot answer any of those
• Scheduling reality: reviewer availability, fieldwork slipping, the report taking longer to write than to earn
• Weekends and holidays, which make every stretch here shorter in working days than it looks
• Whether a shorter window would be accepted, which is a negotiation and not arithmetic
• Evidence that has to be collected from before the window opens, which moves the start date earlier again
• The possibility of a window that has already opened, where the start date is in the past and the arithmetic says so without saying what to do about it

The deadline and the twelve-month period are the buyer's, so the only things you can move are the two legs. Take weeks out of fieldwork and preparation until the start date is no longer behind you — and stop at the smallest total that does it, so you can see how few weeks were the difference.

Reviewer fieldwork6

Weeks between the window closing and the report being issued.

Remediation before the window opens8

Weeks of work that must land before the window starts, not during it.

Day the window must open, numbered from 1970-01-01

20,776

Window opens — year

2,026

Window opens — month

11

Window opens — day

19

Days from today until the window must open

48

Work must start by — year

2,026

Work must start by — month

9

Work must start by — day

24

Days from today until work must start

-8

Days by which that start date has already passed

8

The start date needed for this target is in the past

1

Length of the window in days, as the calendar falls

365

Days from the start date to the report date

463

• Until work must begin
• Start date to report date

◷ Not there yet — keep moving the controls.

Two weeks. Fourteen weeks of legs becomes twelve, and a date eight days gone becomes a date six days away.

That is worth staring at. The thing that broke a fifteen-month plan was not the twelve-month period and not the deadline. It was two weeks in a stretch of time that appeared on nobody's schedule, and the fix was to find two weeks in the same place.

Look at the whole lead time: four hundred and sixty-three days from the start date to the report date, of which three hundred and sixty-five are the period. Ninety-eight days — fourteen weeks — are the two legs. Just over a fifth of the total, and the fifth that nobody is tracking.

Check

Your plan says the period opens on the 19th of November. What would it take to still make the December report with the period opening in January instead?

Choose one answer

Nothing — six weeks either way makes no difference across fifteen monthsA shorter period, or a later report, or less fieldwork — one of the three has to giveMore people on remediation, so the preparatory work finishes fasterBegin the period in January and let the reviewer test it as it goes

Check answer

Where this stops holding: the calendar that is not yours

Everything above treats the fieldwork leg as a number you negotiate. For a large part of the year, it is a queue position.

Most organisations end their period at a quarter or a year end, which means most reviewers have most of their fieldwork arriving in the same few weeks. A six-week leg in March is a six-week leg. The same six weeks starting in the first week of January is the figure a firm quotes while the same firm is holding thirty other engagements that all closed on the 31st of December.

Two consequences, and the second one is the useful one.

The first is that the leg you should plan with depends on when your period closes, and nothing in the arithmetic knows that. The model will happily compute a six-week fieldwork leg across January.

The second is that closing a period somewhere unfashionable is a lever almost nobody uses. A period ending on the 31st of May has the same length, the same cost and the same content as one ending on the 31st of December, and the queue in front of it is shorter. If the report date is what is binding, moving both ends of the period a few months is free in every respect except that it does not match the financial year — which is a preference, not a requirement.

›Why the preparatory leg keeps getting counted inside the periodOptional

It is the most common way these plans go wrong and it is not carelessness. It is a reasonable-sounding sentence: we will stand the controls up in the first month and the period will cover the rest.

What makes it fail is that the opinion is about the whole period. A control that did not exist in month one did not operate in month one, and a reader looking at the period sees a control with eleven instances where twelve were due, or a policy whose approval date sits after the period opened.

The second version of the same error is subtler: the control existed on day one but the evidence did not, because the thing that records it was configured in week three. Nothing failed, and the first three weeks of the period cannot be shown. Both of these are why the preparatory work belongs before the period and why that leg is the one people discover in the final month.

Worth remembering

• Four legs make up the lead time: the reviewer's fieldwork, the period, the preparatory work before it opens, and whatever is left between that and today.
• Fifteen months of calendar with a twelve-month period and fourteen weeks of legs puts the start date eight days in the past.
• Around a fifth of the total lead time is the two legs, and that fifth is on nobody's plan because it is nobody's deliverable.
• Two weeks taken out of the legs was the whole difference between a reachable date and an unreachable one.
• Preparatory work sits outside the period because a control being built did not operate, and because the evidence often starts later than the control does.
• The fieldwork leg is a queue position rather than a number, so closing a period away from a quarter or year end is a lever almost nobody uses.