Whether there is one sender or several involved in preparing the poster.

Whether the senders attend the university and campus from which the data originate.

Whether the senders are involved in business or health-related courses.

The senders' own opinions about vaping on campus.

Other students regularly saying that they always climb trees or place water around game controllers without any problems.

Other bright posters on the wall nearby.

Images that show the opposite of the text-based advice (e.g. climbing trees near power lines when text says not to do this).

Damage to the poster obscuring some of the information.

If there were powerlines and trees near the school and the teachers regularly advised children not to go near them.

If someone in the classroom received a static or electric shock others would be more likely to pay attention to the poster.

If the poster was discussed as part of a class project on safety and first aid.

If a teacher loudly told someone off for asking for help with an electrical device.