Tangible ("hard") benefits are usually measurable in dollars. They include cost savings (lower transaction costs, headcount, expenses, etc.) and increased revenues (higher sales, market share, etc.). At the end of the project, the business will expect to see proof of reduced costs and/or increased revenue. You can generally measure these benefits by comparing monthly financial or sales figures before and after the project.
Soft (intangible) benefits are harder to measure. Although they should be tied to a business goal, the very definition of intangible benefits means that they can't easily be translated directly to dollars. They include
improved employee morale and engagement, increased customer satisfaction, reduced risk, increased alignment with market trends, better regulatory compliance, etc. The soft benefits often have multiple sources and influences; thus, while a project may help improve employee engagement, a variety of other factors may have the same effect, making it difficult to pinpoint the impact of the project.
Improved benefits, whether hard or soft, are grounds for supporting a project. At times, a project may deliver only soft benefits, yet still be worth completing. For example, if new regulations require that an organization change systems or processes, the organization may opt to do so, even though there will be no clear dollar benefits aside from reduced risk of penalties, loss of license, or a negative public image.
Skilled business analysts are able to create a plan for documenting a project's hard and soft benefits in measurable ways. The hard benefits can be measured using cost benefit analysis, transaction timing, process measurement, and other tools. To measure soft benefits, the analyst may need to rely on surveys, focus groups, and other, less precise instruments. The important thing is to plan ahead, identify the expected benefits, and put a benefits realization plan in place for measuring them.