If the " new" 2018 Ancestry DNA estimates are better, does that make the previous results not true ?

In biblical times, pi was reckoned at 3.0. It worked for what it was being used for. Today, 3.14159 is more than adequate for what we use it for and pi has been calculated to many more decimal places. All of the estimates are "true"; some are more precise than others. It's the same with DNA. However, if someone told you that pi = 7.3 or that an obvious Caucasian was 100% Sub-Saharan, those would be false statements.

What part of the word "estimate" don't you understand? Those tests don't compare your DNA to that of people who have been dead for centuries or millennia, but to that of people whose DNA they have

The estimates get better because the databases with DNA-profiles get bigger.

@ William: non-identical triplets SHOULD get different results, because they don't have the exact same chromosomes.

It doesn't make either true. It is not science. People hear DNA and think it is a precise science when it is not.

Even triplets have taken these tests are come up with different ethnic groups as their Ancestry- illustrating the inaccuracy of these results.

If you want to know where your ancestors came from, it requires intense genealogical research.

If the " new " results are making the " old" ones untrue , then what were the old ones based on and how could Ancestry.com have been lying all along ?