Critical Reasoning: Assumption Questions

City Council member: Though offering free bicycle helmets to families with children under the age of 12 will add an additional cost to the city's budget, we should do it anyway to better protect the children. Providing free helmets is in line with our values as a kid-friendly city. When more children wear helmets while riding their bicycles, they experience fewer fatal head injuries. The City Council member's argument depends on which of the following assumptions?

Correct! [[snippet]] If you go back to the argument, you can see that this City Council member's logic is like so: **Providing free helmets to families with children under 12 → fewer fatal head injuries (better protect the children)** Remember that the **assumption** is always the logical step that is **assumed** but not explicitly mentioned in the argument. What's missing in this argument is the assumption that the children will **actually wear the free helmets**. If they don't wear the helmets, then the free helmets alone will not do anything to increase the children's protection. So the City Council member must assume that families will enforce the usage of the free helmets more than they were already enforcing helmet usage. If the families own helmets but never force their children to wear them while riding their bicycles, the free helmets do not make any difference and the argument does not work.

Incorrect. [[snippet]] At first glance, this might *seem* like the correct answer. The author needs to assume that some children will benefit from the free helmets (if **all** children under 12 already own helmets that they use while riding their bikes, then providing free helmets is not likely to provide any additional protection). However, notice that the answer choice says **most**, so 51–99% of children do not yet have helmets. That specifically 51–99% of children do not have helmets is not a foundational assumption for this argument. Imagine that only 5% of children are missing helmets—if this free helmet giveaway provides helmets to those 5% of children and successfully lowers the number of fatal head injuries, then the argument still makes sense.

Incorrect. [[snippet]] It is not a **necessary assumption** that the **most common** accidental death for children is a fatal head injury from a bicycle injury. Even if fatal head injuries from bicycle accidents is the number 10 cause of death, this conclusion could still stand if providing free helmets helps reduce the number of deaths. Therefore, regardless of whether head injuries are the most common types of injuries, this does not change the argument—accidents will still be reduced.

Incorrect. [[snippet]] The City Council member does not have to assume that **all** children in the city under the age of 12 will receive helmets in order for the free helmet policy to protect children. Even if only half or a quarter or fewer children receive free helmets, if those helmets end up protecting the children then the argument makes sense.

Incorrect. [[snippet]] While this might *seem* like a reasonable assumption, it is in fact **not** a necessary assumption for this conclusion. The key word here is ***most***. The City Council member does not **have** to assume that 51–99% of fatal head injuries involve children under 12. Imagine that 75% of fatal head injuries involve children age 12–17 and only 25% involve children 11 and under. Providing free helmets to the families of those children 11 and under could still decrease the number of fatal head injuries among those children and achieve the goal of protecting the children.

Families that receive free helmets will enforce their children's helmet usage more than they had been before receiving the free helmets.

Most children under 12 do not already own helmets that they use when riding their bikes.

The most common accidental death for children is a fatal head injury from a bicycle accident.

All children in the city under the age of 12 who have bicycles will receive helmets.

Most fatal head injuries from bicycle accidents do not involve children over the age of 12.