Multitasking is a productivity illusion

Sutherland cites research and his own field observations to argue that working on multiple projects simultaneously doesn't split your effort efficiently — it actively destroys productivity through the hidden cost of context-switching. Every time someone shifts from one task to another, they pay a tax in lost focus and reoriented attention, and this tax compounds sharply as the number of simultaneous projects grows.

He describes studies showing that people juggling several projects at once can lose a significant share of their effective working time purely to switching costs, and that this loss is largely invisible to the people experiencing it — multitasking feels productive because you're constantly busy, even while actual completed output falls.

His practical recommendation is blunt: assign people to as few concurrent priorities as possible, ideally one at a time, and protect that focus fiercely, rather than praising the appearance of being stretched across many things at once.

Takeaway: fewer simultaneous priorities, done to completion, beat many parallel priorities that all stay half-finished.