Within the past few decades, it has become apparent that the description of chemical reactions based on statistical models like classical transition state theory (TST) or Rice–Ramsperger–Kassel–Marcus theory (RRKM) does not always sufficiently meet reality when it comes to product selectivity and reaction rates. Besides quantum effects like tunnelling events, there are so-called non-MEP (non-minimum energy path) reaction mechanisms involving reaction path bifurcations, roaming and non-statistical dynamic effects. These might lead to product ratios that are not governed by relative barrier heights of competing pathways and therefore pose a challenge for TST-based theories. This perspective will give an overview of tools—experimental and theoretical ones—which have been developed and utilized so far to identify and analyze such dynamic factors in reaction mechanisms. The tools and methods are explained by an eclectic choice of examples—not providing a full review, of the important and ground-breaking work on dynamic effects on various chemical reactions that has been conducted by the groups of Hase, Singleton, Carpenter, Houk and others.