Set and enforce a WIP (Work In Progress) limit

Limit yourself to two to three tasks in the Doing column at any time — never more, even when starting a new task feels easier than finishing an old one.

Why it works

Starting new work is cognitively easier and more rewarding than completing difficult existing work — new tasks offer freshness, autonomy, and an initial hit of progress. Without a WIP limit, this preference for starting over finishing creates a growing queue of half-done work, increasing cognitive load (Zeigarnik effect) and reducing throughput (more items in progress but fewer completing). A WIP limit forces the harder but more productive choice: finish before starting. In queuing theory, limiting queue depth directly improves average completion time (Little’s Law).

How to do it

1. Decide your WIP limit before starting work — for most individuals, two to three is appropriate.
2. Write the limit visibly on the Doing column.
3. When the Doing column is full and you want to start something new, the rule is: finish something first.

Evidence

Little’s Law (throughput = WIP / cycle time) is a mathematical result in queuing theory that applies directly to knowledge work: reducing WIP reduces average cycle time. The Kanban method in software development (Anderson, 2010) reports improved throughput with WIP limits, though these are primarily observational case studies. (mechanistic)

Little’s Law applies to stable systems; knowledge work is variable, and the exact WIP limit is not derivable from the formula — it must be calibrated through experience.

Sources

• Little (1961), a proof for the queuing formula L = λW, Operations Research

Common mistake

Setting a WIP limit but making exceptions whenever "this one is urgent" — every exception moves the Doing column above the limit and reintroduces the multitasking problem.