Small modeling errors may accumulate faster than previously expected when physicists combine multiple gravitational wave events (such as colliding black holes) to test Albert Einstein's theory of general relativity, suggest researchers at the University of Birmingham in the United Kingdom. The findings, published June 16 in the journal iScience, suggest that catalogs with as few as 10 to 30 events with a signal-to-background noise ratio of 20 (which is typical for events used in this type of test) could provide misleading deviations from general relativity, erroneously pointing to new physics where none exists. Because this is close to the size of current catalogs used to assess Einstein's theory, the authors conclude that physicists should proceed with caution when performing such experiments.