The Predictability category answers can we trust our forecasts. Forecasts are only as good as the stability of the system they are drawn from, so these widgets are about variability: how much your system fluctuates, whether a change is a real signal or just noise, and whether that picture is holding steady over time.
- Predictability Score
- Percentiles Over Time
- PBC Over Time
- Process Behaviour Charts
- Arrivals Process Behaviour Chart
Predictability Score
| Applies to | Teams and Portfolios |
| Flow Metric | Throughput |
| Affected by Filtering | Yes |
The Predictability Score is showing you the result of a how many forecast, based on the Throughput Run Chart of the currently selected range. Lighthouse will forecast how many items you can close in the next 30 days based on the specific Throughput run chart.
The overview widget gives you the score at a glance. If you want to inspect how the distribution was calculated, open the details view.
The score is calculated like this:
(Value at 95th Percentile / Value at 50% Percentile) * 100
You can interprete the value as follows:
- The closer you are to 100%, the closer together your 50% and 95% chance are
- If you were at 100%, this means that every single day, you closed exactly the same amount of items, and thus are perfectly predictable
The idea behind the score is that, if your percentiles are very much “away” from each other (meaning the values are far off), the forecast will most likely not be of much use to you. So if your goal is predictability, this can be a trigger for a discussion to see how to “get the score up” and thus become more predictable. Ways to do that include (but are not limited to, and highly depend on your context):
- Asking LetPeopleWork to help you out
- Trying to reduce your batch size, favoring more frequent but smaller delivery
- Reducing WIP and focusing on old items first and get them to done as fast as possible
The goal is not to be at 100%. In fact, that’s far from realistic. We believe any value above 60% is decent. The intent of this chart is to show the results of an MCS for various inputs. For example if the throughput is distributed differently, or you take a longer or different range.
Status Indicator
| Status | Condition |
|---|---|
| 🔴 Act | Score is below 40% — throughput is highly variable and forecasts will be unreliable. |
| 🟡 Observe | Score is between 40% and 60% — investigate whether bulk closings or other patterns are affecting stability. |
| 🟢 Sustain | Score is above 60% — forecasts are considered trustworthy. |
Percentiles Over Time
| Applies to | Teams and Portfolios |
| Flow Metric | Cycle Time, Work Item Age |
| Affected by Filtering | Yes — the chart plots the recorded days inside the selected range, so by default you see the last 30 days for a Team (or whatever range that Team is configured with) and the last 90 for a Portfolio. Widen the pickers to see further back. |
The percentile widgets tell you where you stand today. This chart tells you which way you are moving: Lighthouse records the 50th, 70th, 85th, and 95th percentile once per day and plots each as its own line, so you can see whether your percentiles are tightening, drifting apart, or holding steady.
The lines keep the same red→green ramp as the point-in-time percentile widgets: the 50th percentile is red (least certain), the 95th is green (most certain).
Use the toggle in the widget header to pick what is plotted:
| Selection | What it shows |
|---|---|
| Age | The Work Item Age percentiles of the items that were in progress on each recorded day. |
| 30 days | The Cycle Time percentiles over the trailing 30 days. This is the default. |
| 60 days | The Cycle Time percentiles over the trailing 60 days. |
| 90 days | The Cycle Time percentiles over the trailing 90 days. |
The three Cycle Time horizons are recorded separately, so switching between them looks at the same days through a shorter or longer lens. The 30-day line reacts quickly to a change, the 90-day line smooths it out — if the short horizon moves and the long one does not, you are looking at something recent.
Work Item Age is measured as of the day it was recorded, so it carries no horizon and gets its own tab rather than a set of day options.
This chart builds forward from the day your instance started recording — it is not reconstructed from history. A fresh instance therefore shows “builds forward from today — no snapshots recorded yet” until the first days have been recorded, rather than a fabricated line. The demo data ships with a backdated history, so it is populated immediately. If you select a date range that ended before recording began, the chart says “no data recorded in the selected range” instead — that one is about the range you picked, not about your instance.
Status Indicator
This widget has no status indicator. It shows a direction of travel rather than a value that is healthy or unhealthy on its own — read it alongside Cycle Time Percentiles and Work Item Age Percentiles, which do carry one.
PBC Over Time
| Applies to | Teams and Portfolios |
| Flow Metric | Throughput, Work Item Age, Work In Progress, Cycle Time, Arrivals, and Feature Size (Portfolios only) |
| Affected by Filtering | Yes — the chart plots the recorded days inside the selected range, so by default you see the last 30 days for a Team (or whatever range that Team is configured with) and the last 90 for a Portfolio. Widen the pickers to see further back. |
A Process Behaviour Chart tells you whether a given data point is normal for your system. This chart tells you whether your system’s idea of “normal” is itself moving: Lighthouse records the average and both natural process limits once per day and plots all three over time.
| Line | Meaning |
|---|---|
| UNPL | The Upper Natural Process Limit on that day. |
| Average | The average the limits were derived from. |
| LNPL | The Lower Natural Process Limit on that day. |
On the point-in-time Process Behaviour Charts the limits are neutral, dashed reference lines drawn over your measured data. Here the limits are the data, so each one is drawn solid and in its own colour.
What the shape tells you:
- The band widens — variability is growing. The same process is producing an ever-wider range of outcomes, and forecasts built on it get less useful.
- The band narrows — variability is shrinking and the process is becoming more predictable.
- The whole band shifts up or down — the average level moved. Together with the special-cause signals on the point-in-time chart, this is how you tell whether a change you made actually stuck.
Use the toggle in the widget header to pick the metric family. Lighthouse records natural process limits for Throughput, Work Item Age, Work In Progress, Cycle Time, and Arrivals, plus Feature Size on a Portfolio — a Team has no feature sizes to chart, so that family is not offered there.
The limits are only as meaningful as the baseline they are computed from. Configure it in your Team (Create/Edit Teams) or Portfolio (Create/Edit Portfolios) settings. Without one, Lighthouse falls back to a rolling window ending today — so the recorded limits move as that window slides, for reasons that have nothing to do with your process. On a fixed baseline, movement in this chart is a real signal.
Like the other over-time charts, this one builds forward from the day your instance started recording — it is not reconstructed from history. A fresh instance shows “builds forward from today — no snapshots recorded yet” until the first days have been recorded. The demo data ships with a backdated history, but only for Throughput — so on demo data the other families also start empty and fill in from today, one day at a time. If you select a date range that ended before recording began, the chart says “no data recorded in the selected range” instead — that one is about the range you picked, not about your instance.
Status Indicator
This widget has no status indicator. The point-in-time Process Behaviour Charts carry the special-cause status; this chart shows how the limits behind it have moved.
Process Behaviour Charts
| Applies to | Teams and Portfolios |
| Flow Metric | Cycle Time, Throughput, WIP, Work Item Age |
| Affected by Filtering | Yes |
Process Behaviour Charts (PBCs) help you understand whether changes in your system are likely just normal variability, or whether you are seeing a special cause (something worth investigating).
These charts need a baseline to work. You can configure the bsaeline in your Team/Portfolio settings. If no baseline is set, Lighthouse will use the selected time frame as a baseline. Please note that we recommend setting a baseline in order to make proper use of the PBC functionality.
Configure it here:
- Team: Create/Edit Teams
- Portfolio: Create/Edit Portfolios
On each chart, Lighthouse visualizes:
- Average line
- Natural process limits (UNPL / LNPL)
- Special causes (via the chips in the top-right)
You can click a chip (e.g. Large Change) to highlight points that match that special-cause rule. Clicking on a data point opens a dialog with the work items that make up that point.
If Blackout Periods are configured, those days are highlighted with a hatched overlay on all PBC charts. This prevents you from misinterpreting expected gaps or dips as special causes.
Status Indicator (all PBC charts)
All PBC charts share the same status logic:
| Status | Condition |
|---|---|
| 🔴 Act | No baseline is configured, or a Large Change special cause is detected in any data point. |
| 🟡 Observe | A Moderate Change special cause is detected (but no Large Change). |
| 🟢 Sustain | A baseline is configured and no special causes are detected. |
Cycle Time Process Behaviour Chart
Throughput Process Behaviour Chart
Total Work Item Age Process Behaviour Chart
Work In Progress Process Behaviour Chart
Feature Size Process Behaviour Chart
The Feature Size PBC only exists for Portfolios.
Learn More
Arrivals Process Behaviour Chart
| Applies to | Teams and Portfolios |
| Flow Metric | Arrivals (items started) |
| Affected by Filtering | Yes |
The Arrivals PBC applies the same XmR-chart analysis as the other PBC widgets, but focused on the intake rate. It highlights special-cause variation in how many items are started per day, helping you detect unexpected changes in your arrival pattern.
The Arrivals PBC shares the same status logic as all other PBC charts (see Status Indicator).