Rounding, Six Minutes at a Time
The recording unit decides how much rounding a week contains. Tenths of an hour, applied to forty entries, is two or three per cent a year.
Time is recorded in units: six minutes, fifteen minutes, half an hour. Every task that does not land on a unit boundary rounds, and under a target the rounding is not symmetric.
The data-quality issue in “Rounding, Six Minutes at a Time” begins at the moment an hour is recorded or reconstructed. For organisations researching small business time tracking, examine the reporting options here can organise project-linked time entries, provided people can see, explain and correct their records before those entries affect billing or management decisions.
The effect per entry is trivial. Across forty entries a week and forty-six weeks a year it is two to three per cent.
For an independent reference relevant to “Rounding, Six Minutes at a Time”, consult European Data Protection Board guidelines. Compare the general material with the organisation’s own definition, contract and decision process.
Where the six-minute unit came from
Legal billing, where the client is invoiced per unit and the precision is contractual.
- Six minutes — legal billing, where the client is invoiced per unit.
- Fifteen minutes — common in consultancy, fewer entries per week.
- Half an hour — tasks get grouped, and the per-week rounding falls.
It was imported into firms that do not bill that way, as the history note here describes, and it brought its arithmetic with it.
The asymmetry
A task that took twenty-two minutes can be recorded as 0.4 or 0.3. With a target in place, it is 0.4.
Nobody is lying. Twenty-two minutes genuinely rounds either way, and the person is choosing the defensible option that helps.
The size
Forty entries a week, each rounded up by an average of two minutes, is eighty minutes a week. Against a thirty-five-hour week that is nearly four per cent.
Larger than most of the improvements a firm celebrates.
Why it is undetectable per entry
Because each entry is correct to the unit. There is nothing to find in any individual record.
It is only visible as an aggregate drift, and only if somebody has a reason to look for it.
The larger unit
Fifteen-minute or half-hour units round more per entry and are used fewer times, because short tasks get grouped.
The net effect is usually smaller, not larger, because grouping removes the per-task rounding entirely.
The case for coarser recording
Fewer entries, less rounding, less administrative load, and a figure that does not pretend to a precision the method cannot support.
The objection is client billing, which applies only where the client is genuinely invoiced per unit.
The false precision problem
A figure of 78.4 per cent built from entries rounded to a tenth of an hour, entered from memory at the end of the week, is not accurate to a tenth of a point.
Reporting it to one decimal place invites comparisons the data cannot support, and those comparisons get made.
How the memory part compounds
Most recording is reconstructed, often days later. Reconstruction rounds too, and it rounds toward the memorable and away from the fragmentary.
Short interruptions and administrative tasks are the ones that vanish, which is a systematic rather than random loss.
What to report
Whole hours, or percentages without decimals. The precision of the report should match the precision of the method.
This single change removes a class of argument about differences of half a point between teams.
The daily-recording question
Recording at the end of each day rather than the end of the week reduces reconstruction error substantially.
It also raises the administrative load, and it is a real trade-off rather than an obvious improvement.
The rule worth setting
One recording unit, no finer than the firm's billing requires, stated in the definition, with the reporting precision matched to it.
Three decisions, all in the same sentence as the rest of the definition.
The grouping effect
A person recording in half-hour units does not record forty entries a week; they record twelve, because short tasks get grouped into the block they belong to.
Fewer entries means fewer roundings. The per-entry error is larger and the total is smaller, which is counter-intuitive and is why coarser units often produce more accurate weeks.
It also halves the administrative load, which has its own value and is rarely counted.
What the unit says about the firm
A six-minute unit in a firm that bills by project is a statement that precision matters more than the cost of producing it.
That statement is usually unexamined. The unit was inherited, as the history note describes, and has never been reconsidered against what the firm actually invoices.
Asking the question directly — what is the finest unit our billing requires — resolves it in a sentence for most firms, and the answer is almost always coarser than what they are using. The resistance is not commercial; it is that the recording system was configured once and reconfiguring it feels like a bigger decision than it is.
Matching the reporting to the method
A figure built from reconstructed, rounded entries should be reported without decimals, and movements under two points should not be described as movements.
That is a statement about the precision of the method rather than about anybody's honesty.
Firms that report to one decimal place end up arguing about differences smaller than their own measurement error, which is a guaranteed way to spend meeting time on nothing.
Why this matters more than it sounds
Because a two-to-three per cent systematic drift is the same size as the movements a firm reports as results.
A measure whose systematic error is as large as its signal cannot support the conclusions drawn from it, and the error here is set by the recording unit rather than by anything the firm did.