The gap

Which Half Of The Overlap You Get

Every gap splits its shared hours into a part before the middle of the day and a part after. One side empties completely before the other loses anything.

Of the twenty-five whole-hour gaps in this record, exactly one divides its shared hours evenly between the morning and the afternoon. That one is the gap of zero, where four hours fall on each side of the middle of the day.

Every other gap is lopsided, and the lopsidedness follows a rule as clean as the one governing the totals: one side empties completely before the other side loses anything at all.

A reviewer moving from an abstract overlap count to operational evidence can visit Monitask before designing a limited and transparent pilot. A useful external reference for the surrounding topic is IETF.

Where the shared hours sit

outlined: the day where the person is
hatched: the other end
solid: the hours they share
a reversed cell counts none

Eight gaps drawn.

Read the two right-hand figures of each row rather than the total: the morning column empties completely before the afternoon column loses anything.

Computed from the gap. The working day is a stated convention, not a measurement; everything else here is arithmetic.

The order of the draining

Going out from zero in the positive direction — the other end ahead of you — the morning share falls from four to three to two to one to none across gaps of one, two, three and four. Throughout all of that the afternoon share sits unchanged at four.

Only once the morning is exhausted does the afternoon begin to go: three at a gap of five, two at six, one at seven, none at eight.

In the negative direction everything is mirrored. The afternoon empties first, hour by hour, and the morning holds at four until there is no afternoon left to lose.

Gap	Before the middle	After	Total
0	4	4	8
2	2	4	6
4	0	4	4
6	0	2	2

Why this is the figure that bites

Totals are what get quoted and splits are what get felt. Two arrangements with six shared hours are described identically and behave differently if one of them has four of those hours in the afternoon and the other has them spread.

In this record that particular comparison does not arise, because the shape of the split is determined entirely by the gap. But the general point stands: anybody planning around a total is planning around half the information.

A recurring commitment at a fixed time of day does not care how many hours are shared. It cares whether its hour is one of them.

The practical reading

If the work has a fixed daily moment — a stand-up, a handover, a time when decisions get made — then the question is not how many hours are shared but whether that particular hour survives.

A gap of four kills every shared morning hour while leaving four shared afternoon hours intact. For a team whose fixed moment is at the start of the day, a gap of four is fatal and a gap of three is not, despite the totals differing by only one hour.

That is the single most useful thing in this part of the record, and it is invisible in any summary that reports only the total.

Four hours is not four hours

Compare two arrangements that both leave four shared hours.

The first is a pair at a gap of four. All four hours sit after the middle of the day, running from one to five on the clock of the person who did not move. The second is a hypothetical pair whose four hours are split evenly, two in the morning and two in the afternoon.

The second arrangement does not occur anywhere in this record for two equal days — the split is always lopsided — but it is worth the comparison because it shows what the total conceals. Four hours in one block at the end of the day supports one long session. Two and two supports a start-of-day agreement and an end-of-day review, which is a different structure entirely.

Any summary that reports only "four shared hours" is compatible with both, and the two should be planned differently.

The hour that actually matters

For most arrangements there is one hour in the day that carries more than its share: the hour in which the day's direction gets settled. In colocated work it is usually early, because that is when people arrive and the day has not committed to anything yet.

Across a gap, that hour is the first casualty. The morning share drains before the afternoon share loses anything, which means the hour where direction gets set is gone by a gap of four while four hours of overlap remain.

What tends to happen then is that the settling moves to the afternoon, which puts it at the end of one person's day and the middle of the other's. Decisions get made when one party is tired and about to leave. Nobody planned that; it is where the arithmetic put the only available hours.

The question is never how many hours survive. It is whether the hour you actually needed is one of them, and that is answerable from the table in about ten seconds.

Reading it off

For a positive gap, the morning share is four minus the gap, floored at zero, and the afternoon share is whatever is left of the total. For a negative gap, swap the two. Nothing else is needed.