Which method would a researcher use to assess the impact of intervention without calculating exact differences?

The use of vote counting is appropriate for a researcher seeking to assess the impact of an intervention without delving into the specifics of calculating exact differences. This method involves tallying the number of studies that report positive effects versus those that report no effects or negative effects, providing a straightforward, qualitative overview of the overall evidence regarding an intervention.

Vote counting is particularly useful in scenarios where exact numerical values are not necessary, as it gives a snapshot of the general trend across multiple studies in a very accessible format. It allows researchers and practitioners to get a sense of the prevailing evidence without requiring extensive statistical analyses or calculating effect sizes, which may be more complex and data-intensive.

In contrast, the other methods involve more rigorous statistical computations or analyses. Statistical modeling requires mathematical techniques to describe relationships between variables, effect size calculations involve deriving a numerical value representing the magnitude of an intervention's effect, and meta-regression is a sophisticated analytical approach to understand how various study characteristics affect outcomes. These approaches are valuable but go beyond the simple assessment of whether the evidence supports a positive or negative effect.