Construction site timesheet: working out person-days from a WhatsApp message

“Structural crew 12 people, rebar crew 4 people half day.” This single line the foreman sends in the evening has to become a calculation in the office. A person-day is a timesheet measure: the number of people working on a job multiplied by the number of days they worked. If you count a half day as 0.5, as is common practice, the message above comes to 12 + (4 × 0.5) = 14 person-days; if your company’s rule is different, of course that rule applies.

The calculation itself is simple. The hard part is doing it every evening, for every site and every subcontractor, by reading scattered messages. In this article we explain where person-day calculation breaks down and how the work runs with SahaSesi AI.

Why is it hard to get person-days from a message?

• Who is being counted? “The structural crew” is a subcontractor group, “Mehmet the craftsman” is one person. In the timesheet they are separate lines.
• How many people? “There were twelve of us but three left at noon” is not one number but two separate records.
• Full day, half day or overtime? The same person may have worked both a full day and overtime on the same day.
• Which day does it belong to? If a message written late in the evening, or a “yesterday” message that arrives the next morning, is recorded on the wrong day, the month-end table goes off.
• Split messages. A foreman may send one sentence as three separate messages; the office has to read them as a single record.

Each of these uncertainties is small on its own. But with several sites, several subcontractors on each, and dozens of messages every evening, the office spends more time interpreting messages than calculating the timesheet. At month end the subcontractor brings the number from their own notebook, and the reason for the gap between the two figures cannot be found.

How does a message become a timesheet entry?

1. The foreman writes or leaves a voice message. SahaSesi AI separates the message out as a timesheet record; the record is processed per person or per subcontractor crew, with half days and overtime kept apart. Messages sent one after another by the same person are evaluated together.
2. The record is read back. The foreman receives a reply such as “Saved: …”. If the number is wrong, the foreman writes “no, it was 10 people” and the record is corrected.
3. A message that cannot be confidently understood goes to the office. A message that cannot be processed or stays unclear appears in the “awaiting review” list; no record is silently lost.
4. A forgotten timesheet is reminded. The foreman of a site whose timesheet has not arrived by the reminder time receives a reminder on WhatsApp.
5. The day closes, the month is totalled. The day’s records are arranged into the daily report; once the site manager approves, the report is locked. The monthly timesheet table is exported to Excel per person and per subcontractor, day by day, with half days and overtime.

A hypothetical week: where do 54 person-days come from?

The figures below are made up; the aim is to show how daily messages add up to a total by the end of the week. A half day is counted as 0.5.

• Monday: structural crew 12 people, full day. Total 12 person-days.
• Tuesday: structural crew 12 people full day, rebar crew 4 people half day. Total 14 person-days.
• Wednesday: structural crew 12 people, rebar crew 4 people, both full day. Total 16 person-days.
• Thursday: work stopped because of rain. No timesheet; but the stoppage is recorded separately as an incident and goes into the daily report.
• Friday: structural crew 12 people, full day. Total 12 person-days.

The week’s total is 12 + 14 + 16 + 0 + 12 = 54 person-days. Instead of adding these lines up one by one at month end, having the daily records already side by side per crew makes both the total and a question like “how many days did the rebar crew come this week?” easier to answer. A timesheet left to month end, on the other hand, turns into an argument about a day nobody remembers.

Which day does a late message go to?

On a construction site there is not always signal. WhatsApp holds the message on the phone and sends it by itself when signal returns. In SahaSesi AI the record is written to the day the message arrived; if the message contains an explicit expression such as “yesterday”, it is processed back by up to three days. This rule reduces the chance of the timesheet silently landing on the wrong day but does not remove it; that is why it matters for the office to check before the day closes.

A good timesheet is not the one that does the cleverest calculation, but the one that shows the error earliest.

A short checking routine for the office

• In the morning, check whether yesterday’s report shows any site marked “no record received”.
• In the evening, do not approve the day before closing the awaiting-review list.
• At month end, lay the Excel timesheet side by side with the subcontractors’ own crew lists.
• If a gap with a subcontractor appears, look at the record for that day and at the change history; every change leaves a trace, so you can see where the gap arose.

SahaSesi AI is being introduced at the first sites through a pilot programme. To see your person-day process with your own site’s messages, you can arrange a pilot meeting on the SahaSesi AI page.