We try our best to ensure that the data we publish are accurate and complete before, during, and after they are published. This page lists all of the corrections that we have made.
We may make changes that are not corrections. For example, our Traffic graphs do not show graphs of Google's actual traffic numbers. Rather, the graphs display interruptions in service that are specific to a geographic region. If changing how we generate the data will better serve that goal, we'll make the revision and add a note here to explain it.
By maintaining this change log, we hope to strike a balance between keeping a good historical record, and allowing ourselves to make improvements.
From time to time, Google changes how it classifies incoming traffic. This may result in changes to our graphs that do not reflect any actual changes in traffic to our services.
September 2011. We corrected errors in our graphs which caused anomalies that were most visible between September 19-23, 2011.
March 2011. We fixed a bug that was causing spurious traffic spikes to appear toward the end of the day in a small number of graphs, especially graphs for Iran.
Transparency Report