For each section of your DNA, Ancestry Composition assigns a probability to each reference population for a given segment of DNA. We assign populations at five different confidence levels ranging from conservative to speculative. You can select the confidence at which these populations are assigned within the Scientific Details section of Ancestry Composition.
The default Speculative Estimate corresponds to 50% confidence. You have the option to make the estimate more strict, meaning that the interpretation shown is more likely to be accurate. While the conservative view of Ancestry Composition displays the ancestry assignments that we are most certain of, you will see more assigned ancestry in the speculative view.
You can read more about how the confidence threshold works in the "Aggregation & Reporting" section of the Ancestry Composition Guide.