The Data Quality Process for XMM-Newton Data

Each Observation panel in the Results list contains a link to a data "Quality Report". Here follows a short description of its generation.

A data quality process is being systematically applied to all XMM-Newton data since the beginning of the mission. Pipeline processing of all XMM-Newton ODFs is part of this process. The successful SAS processing of an ODF normally proves that it is "well formed", i.e. compliant with the formal specification.
Each ODF is also screened at the XMM-Newton Science Operations Centre prior to shipping to Science Survey Centre (SSC), to check for pre-processing anomalies, such as attitude jitters, time reconstruction jumps, telemetry losses, housekeeping out-of-limits, counting mode in EPIC exposures, and a correct field acquisition for OM exposures.

The "formal compliance" does not imply that the scientific results can be trusted and properly reflect the status of the instrumental calibrations.
For this reason the Science Survey Centre coordinates a large international effort to systematically screen and verify the scientific quality of all the PPS products generated by the automatic processing pipeline. The result of this effort is summarized in Data Delivery Notes (DDNs), which are attached to the suite of pipeline products distributed through the XMM-Newton Science Archive.

The Quality Report linked from the XSA user interface combines the contents of the results of the SOC pre-processing screening and the SSC DDNs.

The Data Quality Report lists the anomalies discovered during a given observation, in a verbose form, which should allow even non-expert XMM-Newton users to understand their meaning and implications. Nonetheless, if something in them remains obscure, you may move the cursor onto the corresponding string in the Data Quality Report: a tool-tip on-line help item will appear, with more explanations. If further details are needed, you may consider to contact the XMM-Newton HelpDesk for advice (if available).