This is a bonus episode recorded live with audience pre-covid-19 at the Conversion Hotel conference in November 2019 on the island of Texel in The Netherlands. (oorspronkelijk gepubliceerd op https://www.cro.cafe/)
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.