Investment appraisal helps both businesses and governments make smart decisions about where to invest money. Different methods like payback, average rate of return, and discounted cash flow are used to figure out which projects will make the most money or have the biggest impact. Cost-benefit analysis is a key tool that looks at the social and economic costs and benefits of investments. However, it can be tricky to put a price on things like time or happiness. This analysis is more common in government projects because businesses don't always have the data or need to calculate these social factors.