In the context of public goods, how does the free rider problem complicate cost-benefit analysis when evaluating whether to provide a public good?

Public goods are things that everyone can use, like clean air or national defense, and they are usually paid for by the government or community. The free rider problem happens when people benefit from a public good without paying for it, which can make it hard to figure out how much the good is worth to society. When conducting a cost-benefit analysis, it becomes tricky to measure how much people value the good because many might not contribute, thinking they can still enjoy the benefits for free. For example, if a city wants to build a new park, some people may enjoy it without donating money for its upkeep, making it difficult to assess if the park's benefits outweigh its costs. This issue can lead to underfunding or not providing the public good at all, even if it would be valuable to the community.