Not just valid, I’d argue important. It doesn’t make the most exciting headlines and doesn’t get funding very well, though, so it’s not done nearly as often as it should be. A big part of science is not taking things at face value and verifying that there is sufficient proof for claims.
Plus, if both results agree, it statistically tightens the probability of a coincidence. The chances of a 5% chance event happening twice in a row is 0.25%, and three times in a row is 0.0125% so repetition can make the results more certain.
Is it valid science if you re-test the one that had the link to see if it was a fluke?
Not just valid, I’d argue important. It doesn’t make the most exciting headlines and doesn’t get funding very well, though, so it’s not done nearly as often as it should be. A big part of science is not taking things at face value and verifying that there is sufficient proof for claims.
Plus, if both results agree, it statistically tightens the probability of a coincidence. The chances of a 5% chance event happening twice in a row is 0.25%, and three times in a row is 0.0125% so repetition can make the results more certain.