What does Little's Law tells us?

Question

Options

• AThe easiest way achieve flow is to reduce queue lengths.
• BLong queues help increase process efficiency.
• CThe easiest way to reduce waits is to increase the processing rate.
• DThe average wait time is dependent on the varying arrival rate of items coming into the queue.
• ESingle-piece flow is always best.

• A
  92% (22)
• C
  4% (1)
• D
  4% (1)

Explanation

Option A is correct because Little's Law (W = L/λ, where W = wait time, L = queue length, λ = throughput) shows that wait time is directly proportional to queue length - so shrinking the queue is the most direct and actionable lever for improving flow, and generally easier than dramatically increasing processing capacity.

Why the distractors fail:

• B inverts the relationship - longer queues increase wait times, not efficiency.
• C is a valid strategy but not what Little's Law emphasizes as easiest; the law highlights queue length (L) as the primary control variable.
• D misrepresents the formula - Little's Law uses average arrival rates in steady state, not varying rates; wait time depends on queue length relative to throughput, not fluctuating arrivals.
• E is a separate Lean principle (single-piece flow) not derived from Little's Law itself, and "always best" is too absolute.

Memory tip: Think of Little's Law as "Less Line = Less Wait." The formula W = L/λ makes it visual - if you can't speed up the server (λ), cut the line (L). The easiest fix is always attacking the queue directly.

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