The classic scene: you are ringing up a sale, the store phone rings, a customer asks for a size from across the floor, and the courier leans in waving a delivery note. You "handle it all". And indeed: the receipt comes out with the wrong price, you return the phone call ten minutes later to a number jotted down wrong, and the size they wanted was a different one.
It felt like peak efficiency. The result is three errors in four minutes. It is not your fault: multitasking simply does not exist.
The brain does not parallelise: it alternates, and pays a toll
Decades of attention research say one thing in many voices: what we call doing several things at once is actually jumping rapidly between tasks, and every jump has a cost. It is called switching cost: a few seconds to rebuild context, plus an error rate that climbs with every switch. In the lab it gets measured; in a store it is called wrong change, a half-recorded return, a forgotten promise to a customer.
People who are "great at juggling a thousand things" do exist, but their real skill is different: choosing fast what to drop. And that is exactly the skill you can teach the whole team.
A hierarchy said out loud
The organisational mistake is not that interruptions exist: it is letting each person decide alone, every single time, what comes first. The fix costs one ten-minute meeting: agree the hierarchy of interruptions and pin it in the back. One version that works in many stores: first, the customer in front of you at the till (money in hand is never abandoned midway); second, the customer on the floor; third, the phone, which can take a message; last, the courier, who can wait ninety seconds.
It is not the only possible hierarchy: it is yours to decide. The point is that it exists, because it strips every interruption of the power to win merely by being loud.
Fragile tasks get protected, not squeezed in
Some tasks do not tolerate interruption: the till count, a complex return, the paperwork on a large order. Squeezing them "into the gaps" means doing them twice. The right practice is declaring them: "two minutes, closing the till" said out loud to a colleague works like a sign on a door, and routes interruptions to the other person for that stretch.
Which is also why certain chronic errors are not a people problem but a coverage problem: if some slots have a single person in them, every fragile task is hostage to the door. The solution there is not concentration. It is the plan.
The phone deserves its own paragraph
Half of many stores' interruptions come from the phone, and half of those calls ask things a well-crafted voicemail or one line on the website would answer: opening hours, availability, "are you open on Sunday?". A good recorded answer is not coldness: it is how you save the real humans for the real questions.
Knowing in which time slots your coverage can absorb interruptions and in which it cannot is the first step: the planning view in Sked Solve puts it right in front of you, as the site shows.