eg: My noise-reduction strip that’s fixed below my door is designed for large gaps (like 2cm) below the door. For my door, its effectiveness is unnoticeable.

eg: Many foods are “proven” to help weight loss, but sponsored research deliberately recruite obese participants. For my family members (and many friends) who are marginally overweight, the effectiveness is questionable.

eg: Online learning sites, and some video-based tablet devices are designed for primary/secondary level students to learn on their own. They are “shown” to improve grades, but shown uisng a sample of students who are already keen on self-learning, or samples of students without classroom facilities. For most Singapore students I know, the effectiveness is questionable. These students are already overloaded with classroom-based, exam-driven learning with heavy homework.