Researchers may not have measured all the outcomes that matter to you in studies that compare interventions, and the ones they have measured may not matter to you.
For example, studies often measure outcomes that are easy to measure, such as bird numbers for outcomes that are less easy to measure, such overall farmland biodiversity.
However, the effects of interventions on those substitute (surrogate) outcomes do not always provide a reliable indication of the effects on the broader outcomes. Similarly, short-term effects may not provide a reliable indication of long-term effects.
REMEMBER: Ask whether the outcomes that are important to you have been measured in fair comparisons of interventions, and look out for surrogate outcomes.