Economic values are often an important determinant. This value requires analysis of how a decision will impact the various stakeholders financially.
Ethical values have to be considered as well. This involves considering what actions or outcomes would be considered to be morally acceptable or unacceptable. This is often a very difficult thing to analyse, as it's entirely subjective, and some future consequences that might change individual's minds may be difficult to foresee.
Risk management is another consideration. Some individuals or societies are more accepting of risk than others. The probability of a bad outcome from a given decision needs to be calculated, so the decision can be evaluated.
The three major types of values are:
1. Financial or monetary value is the cost of providing the necessary physical facilities that allow us "to make a specific environmental decision".
2. Economic values are specific impacts (such as, jobs created or incomes generated, etc. etc.) that result from the implementation of the "said environmental decision".
3. Social values are specific impacts (such as, social cohesion, preservation of native communities, family values, etc.) that result from the implementation of the "said environmental decision".
In fact, the environmental values itself can be measured by several different parameters, such as physical/chemical impacts, human health or biological impacts, ecological impacts, aesthetic impacts, etc. etc..