Economic value is a measurement of benefit produced by a good or service. Usually, this benefit is measured in a common currency in order to make these goods and services comparable. The theory of value is used in everyday situations without much consideration. For example when considering my preferences and constraints at the moment, I would be willing to spend $10 for a good sandwich right now. Regardless of what the actual selling price of a sandwich is, I have my own personal value for the good.
When talking lunch items, I have no problem valuing these items in terms of dollars. In many political decisions, however, policy makers are faced with the impossible job of setting a value to all sorts of things such as the environment or even the human life.
How much is clean air worth in the economy? How do we measure it? Are young people more valuable than the elderly? Who gets to make these decisions anyway?
Monetizing priceless commodities is a dreadful problem with two main elements. First of all, we must deal with the morals. Some people believe that it is unethical to put a price tag on a human. Others (and by others I mean those heartless economists) believe that it is important to compare the costs and benefits of every potential policy. This includes comparing the costs of implementing a new policy that saves lives to the benefit of the potential lives that would be saved. Without a common term in which we can make comparisons, there is no way to tell if a policy or decision would be justifiable.
Without considering morals, there is still a problem in how the valuation is calculated. Depending on what type of good or service you are presented with, the approaches may differ. National parks, for example, gather information from their visitors including attendance rates and willingness to pay. From there, they can make estimations to the value of their parks. People, on the other hand, are valued in terms of their attributes including age, education level, career, etc.
Approaching this subject is tricky. There is no right or wrong answer that can provide a solution but the process is incredibly important.