What happens after laboratory tests confirm that an environmental product kills bacteria? Is that the end of the line for testing a product's efficacy? One pair of researchers say no. Here is their proposal for an evidence hierarchy that describes how, in theory, data can begin to connect a product to a reduction in HAIs. While many regulatory agencies exist to protect the consumer by ensuring that HAI reduction claims are true, it is important for us to still be aware of the burden of proof in research, and how that plays out in a laboratory and real-life setting.