We prefer products from stereotypical countries. For example – Germany is typically known for building good cars, whereas the French produce the best wine, the Swiss the best watches, and the Japanese are known for good TV sets.
To use this, you first need to know if the country of origin of your product complies with the stereotype or not. If it does comply with the stereotype, you can (subtly) remind customers of this fact or show other stereotypical items of that country. If the product doesn't comply with the stereotype, you might consider not mentioning it (or less prominent) or try to counteract the stereotype by showing other quality products from this country.
Recently I've seen some (often absolute) statements going around, generally in the line of "open source commerce platforms are a terrible idea". Now of course different solutions always have different pros and cons.
A hierarchy of evidence (or levels of evidence) is a heuristic used to rank the relative strength of results obtained from scientific research. I've created a version of this chart/pyramid applied to CRO which you can see below. It contains the options we have as optimizers and tools and methods we often use to gather data.