Is there a quantitative or qualitative assessment that measures the specific assumption in the link? If yes, then there is evidence for this link. If no, there is not evidence for this link. The purpose of this step is to identify whether evidence exists for the actual assumption, not its potential. Evidence can come from quantitative meta-analysis, key informant interviews, traditional knowledge, or many other sources here as in other uses of evidence, but it must be used to assess the specific assumptions.
For example, continue the wind results chain, and consider the first assumption that utility requirements for companies to avoid sensitive grassland areas lead to utilities purchasing power only from those companies that do so. Evidence for this assumption may come from utility power purchase records (quantitative), or from interviews with managers from wind power producers (may be quantitative or qualitative). If in manager interviews, managers say they think utilities will purchase more wind power from them in the future after they change practices because they have a good relationship with the utilities, this does not constitute evidence. If, however, managers say they have had higher sales to the utilities after improving siting practices, that qualitative information constitutes evidence for the assumption because it reflects a direct observation that the assumption is true.
In the process of evaluating evidence, teams will likely find they need to hone the language in the results chain, to be more specific about assumptions and causal mechanisms of change that are implicit in the diagram. For example, consider the following example from northern Australia:
Often, results chains are worded ambiguously. Thus, a first step in assessing the evidence for a results chain is to be re-word the results chain so that it is clear what evidence is required. The revised results chain below is more specific.
Note that even a specific results chain will require definition of terms. In this example, it must be clear to readers what is meant by ‘early season burning’, ‘vegetation communities of conservation concern’ and ‘native fauna’. Evidence searching will be easiest when results chains are highly specified.