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Methodology

What the indices measure, where the data comes from, and how quality is kept honest

Congestion index

Each anchorage and each port gets an hourly score from 0 to 100. The score compares the current waiting load with that area's own history, so 50 means a typical busy hour for that place and higher means heavier than usual. Ports of different sizes are therefore comparable, and an empty anchorage scores 0.

Port call detection

A port call is recorded when a vessel actually stops: waiting in an official anchorage area, or staying alongside in the port. Ships that only pass through an anchorage on their way in or out are not counted. Arrival and departure times reflect when the vessel stopped and when it got under way again.

Anchorage areas

Anchorage boundaries come from official published sources for each port (port authority notices, national open data and federal regulations), credited below. Berth stays are inferred from vessel behaviour where no official berth boundaries are published.

Wait forecasts

Expected waits are shown as a range (median, P80, P95) rather than a single number, learned from this platform's own history of completed calls and adjusted to current conditions in the port. Each forecast states how many past calls it rests on.

Data quality

AIS is noisy: positions may be missing, delayed or wrong. Implausible reports are filtered before analysis, short signal gaps are tolerated, and long gaps close an open call at the last confirmed report. Nothing is interpolated or smoothed over silently.

Validation

Predictive features ship behind a flag and are validated on held-out history before any forecast is shown.

Accuracy and validation

We compare our port-call counts with an independent public reference and publish the agreement for every port on the coverage page, including where it is weak.

Data sources

Every number names its sources, how fresh it is and how confident we are, behind the "Why this number" chip next to it. The full list of sources, licences and known blind spots is on the coverage page.

Data sources and licences

This dataset is described as structured data for reuse.