The intraday profile
Slides done? Here’s the same idea in a bit more depth — the part worth keeping.
In depth: how a daily total becomes a roster
“We’ll get 4,000 contacts on Tuesday” is a forecast that tells you almost nothing about staffing. Four thousand contacts spread evenly across the day needs a flat team; the same four thousand bunched into two sharp peaks needs a completely different shape. Staffing is decided at the interval level — every 15 or 30 minutes — so the daily total is only useful once you know how it’s distributed across the day. That distribution is the intraday profile, and it’s the bridge between a forecast number and an actual roster.
What the profile is, and how to build it
The profile is simply the share of a day’s volume that lands in each interval — a list of percentages that sums to 100%. You build it by taking several weeks of history, working out what share of each day’s total each interval carried, and averaging those shares across comparable days. That last word matters: a Monday profile is not a Saturday profile, and many operations need a distinct shape per day of the week, plus separate profiles for paydays, post-campaign spikes or peak season. Once averaged, you normalise the profile so it adds to exactly 100% — now it’s pure shape, independent of size, ready to multiply onto any daily forecast.
The three ways it goes wrong
The most common mistake is one all-purpose profile applied to every day — your daily total can be perfect and your interval staffing still wrong from open to close. The second is staleness: profiles drift as opening hours change, self-service moves the peak, and customers learn to call later, so they need refreshing. The third is dirty history — a single outage or fire-drill day left in the average can dent the shape for months, which is why cleaning the history comes first. Get those right and the final step is trivial: tomorrow’s daily forecast times each interval’s percentage gives the interval-level volume that Erlang turns into headcount.
The principle to remember: the total tells you how much, the profile tells you when. Build one per day type, keep it normalised and refreshed, and multiply it onto the daily forecast — that’s how a number becomes a roster.
Quick quiz
Five questions. Pick an answer to each, then check your score.
1. What is an intraday profile?
It’s the day’s shape — a percentage per interval that adds up to 100%.
2. Why isn’t a daily total enough to staff a day?
Same total, different profile, different roster. The shape decides where people need to be.
3. Should you use the same profile for every day of the week?
Different day types have different shapes. One all-purpose profile mis-staffs the days that don’t fit it.
4. How do you turn a daily forecast into an interval forecast?
Daily forecast × profile percentages = interval volumes — the input Erlang needs.
5. What can quietly distort a profile over time?
Profiles drift and dirty days dent the shape — refresh them and clean the history first.
Turn interval volume into headcount with the Erlang C calculator, or go deeper in The Forecasting Masterclass.