One key flaw of the design where four age groups (20, 30, 40, and 50) are asked about their support for decriminalization of marijuana for medical purposes is that it may not adequately control for social or cultural factors that vary with age and could influence viewpoints independently of age itself. This means differences in opinion might reflect cohort effects or cultural influences rather than pure age-related changes in attitude
. Additionally, the design excludes other age groups (e.g., teenagers, older adults beyond 50), which limits the generalizability of the findings and may miss nonlinear patterns in support across the lifespan
. Without controlling for these confounding variables or including a broader age range, it is difficult to attribute differences in viewpoints solely to age. In summary, the main flaw is the potential confounding of age effects with social or cultural influences and the limited age range sampled, which can bias interpretation of how viewpoints change with age
