Throughput and Work Item Aging

Throughput is the number of work items completed per unit time.

• "We delivered 8 features this sprint"
• "Our weekly throughput is 5-7 items"
• "This month we completed 32 items"

Throughput tells you about the capacity of your system. It's the output rate.

Relationship to other metrics (Little's Law again): WIP = Throughput × Lead Time

If you know any two, you can calculate the third.

Like cycle time, throughput varies. Understanding the variation is crucial.

Track throughput over time:

• Week 1: 6 items
• Week 2: 8 items
• Week 3: 4 items
• Week 4: 7 items

Average: 6.25 items/week Range: 4-8 items/week

This tells you: "We can usually deliver 4-8 items per week."

Causes of throughput variation:

• Team capacity changes (holidays, sick days)
• Item size variation
• Blockers and dependencies
• Work type mix
• Random variation (it's normal)

Stabilizing throughput:

• Consistent WIP limits
• Right-sized work items
• Addressing blockers quickly
• Predictable capacity allocation

Item age is how long a work item has been in progress (started but not finished).

It's a leading indicator—it tells you about problems before they show up in cycle time.

Why track aging:

• Long-running items often have problems
• Early warning before cycle time blows up
• Visible signal for intervention

Using age thresholds: If your 85th percentile cycle time is 8 days, set an alert at that threshold:

• "This item has been in progress for 9 days. That's above our 85th percentile. What's happening?"

Aging report format: List items by age, compare to percentile thresholds:

• Items aged 0-3 days: 12 (normal)
• Items aged 4-8 days: 4 (watch)
• Items aged 9+ days: 2 (investigate)

The action: When an item crosses into "investigate" territory, have a conversation. Don't wait for it to finish and blow up your metrics.

Some teams use velocity (story points per sprint) instead of throughput (items completed).

Problems with velocity:

• Story points are estimated, not measured
• Different teams point differently (no comparison)
• Encourages gaming ("let's inflate points")
• Conflates size with time

Benefits of throughput:

• Objective measurement (an item either completed or didn't)
• Comparable across teams (if items are similar)
• No estimation required
• Combined with item aging, more actionable

The pragmatic approach: Use throughput for flow metrics. Use story points if they help your team plan (many find them useful for sizing). Don't mix the two.