Track’s Calculated Events feature helps you to stay on top of shipments that may have gone missing, or which have passed their delivery promise date. This page explains the shipment properties that Track can calculate, how calculated events work, and how best to use calculated events

What is a calculated event?

A calculated event is an event that is generated by Track’s internal processing, rather than as a result of an external tracking update.

Each shipment has two properties that Track can change without receiving a carrier tracking update. They are:

  • may_be_missing - Indicates whether Track believes that the shipment may be missing. Track marks shipments as may_be_missing if they are not updated within a set time period after registration, or if they are not marked as delivered, lost, or refused within a different set time period.
  • lateness. Contains two sub-properties - lateness.is_late and lateness.hours_late. These properties indicate whether Track believes a shipment to be late, and (where applicable) how many hours late this shipment is.

When Track updates one of these properties, it creates a calculated event to record the change. You can retrieve calculated events in the same way you would retrieve regular, carrier-derived events.

May be missing

If Track believes that a shipment may be lost, it sets that shipment’s may_be_missing property to true. By default, the may_be_missing property is set to false.

Track sets a shipment’s may_be_missing property to true if either of the following conditions are met:

Condition 1

No state changing tracking event has been received for that shipment within 12 hours of the shipment being registered with Track (as recorded in the created_on property) OR within 12 hours of the shipped_date (whichever is earlier). Note that shipped_date is an optional field.

Condition 2

All of the following conditions are met:

  • The shipment has never been in any of the final states.
  • The shipment has a country ISO code registered for both its origin and destination addresses (via the addresses.country_iso_code property).
  • It has been more than 24 hours since a tracking event was received for a domestic shipment, OR more than 72 hours since a tracking event was received for an international shipment.

Shipments are classed as domestic if their origin and destination addresses.country_iso_code is identical. Otherwise, they are classified as international.

Is late

The lateness.is_late property denotes whether Track believes a shipment to be late. By default, the is_late property is set to false. Track sets is_late to true if all of the following conditions are met:

  • The shipment has a promised_date recorded.
  • The date and time recorded in promised_date has elapsed.
  • The shipment did not enter any of the final states before the promised_date elapsed.

If a shipment does not have a promised_date recorded, then Track cannot perform lateness calculations for that shipment.

If a shipment is marked as late, then Track records how many hours late it is in the lateness.hours_late property. This information is refreshed every time the shipment is retrieved from the Tracking, Shipment or Events APIs.

The is_late flag is reset if the shipment is updated with new promised_date information (as long as the new promised_date has not also already elapsed). If is_late is reset to false, then hours_late is reset to NULL.

Trackable shipments

To optimise performance, Track periodically marks old shipments as “non-trackable”. The system only performs may_be_missing and lateness calculations on trackable shipments.

A shipment is deemed to be non-trackable if any of the following criteria are met:

  • The shipment is domestic (i.e. the addresses.country_iso_code of its origin and destination addresses is identical) AND Sorted has not received a tracking event for it in seven or more days.

  • The shipment is international (i.e. the addresses.country_iso_code of its origin and destination addresses is different) AND Sorted has not received a tracking event for it in 10 or more days.

  • The shipment is in a final state AND Sorted has not received a tracking event for it in three or more days.

Final states

A final state, usually known as a terminating state, is when no further shipment processing is required. When a shipment goes into a final state it will not change, however Track will still process additional events from the carrier.

Calculated States uses final states to help calculate if a shipment is late or missing. For more detail on final states, visit our tracking states guide.

Calculated properties

Although set by Track, the lateness and may_be_missing flags are standard properties and can be integrated in exactly the same way as any other shipment data. They are returned by the Shipments and Events APIs, as part of the Shipment and Shipment Events resources.

View calculated properties

The UI’s Calculated Events dashboard displays the number of your shipments that Track has flagged as Late or May Be Missing.

To open the Calculated Events dashboard, hover on the Dashboards icon on the left and select Calculated Events.

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Next steps

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