Today the CTA SIP provides latency statistics via the CTA Plan website under the SIP Metrics tab; these statistics represent measurements within the SIP, from the point of receipt by the SIP to the point of dissemination from the SIP. In order to provide the industry with additional transparency related to message latency the CTA Plan has approved the creation and publication of "Realized Latency Charting" at the 10%, median (50%) and 99.9%.
Realized Latency is the measurement from the inception of the Participant matching engine event (e.g. order execution, top of book update) to the point of dissemination from the SIP. Providing latency statistics based on measurements from the point of inception of an event (participant timestamp within the data feed message) to the point of SIP dissemination (this is currently not captured within the data message) should provide SIP data feed consumers with a gauge of transactional latency that is more reflective of their experience.
As a companion delivery to the published charts, a CSV file is available for access, providing a broader range of percentiles (median, 10, 90, 95, 99, 99.9, 99.99) by Participant and data feed, such that anyone could easily generate their own graphs and will have access to the necessary data to do so.