@bidens_diaper @J_D_Klein @HalCranmer The real world is always going to be messy. That's true whether you are studying masks in schools or fish population in a lake. No one would claim these or any studies are without 'flaws'.
@拜登尿布@J_D_Klein@HalCranmer现实世界总是一团糟。无论你是在学校研究面具，还是在湖中研究鱼类种群，都是如此。没有人会声称这些或任何研究都没有“缺陷”。