The phrase "insignificant impact" means that something has a very small or negligible effect or influence. It doesn't make a significant difference and is not important. Full definition
However, such problems are generally «short - term» and are considered to have a relatively insignificant impact on the overall health status of the dog. (thebedlingtonterrierhealthgroup.webplus.net)
In secondary schools, they found that per - pupil funding had a small positive, but statistically insignificant impact, on attainment. (schoolsweek.co.uk)
We find evidence of large, statistically significant impacts on African Americans, but fairly small and statistically insignificant impacts on Hispanic students. (educationnext.org)