Many companies make the mistake of trying to put a value on their data warehouse. The truth is the value of the warehouse stems from the new and changed business processes that it enables. Thus, in developing a warehouse it is extremely important to envision who is going to use the warehouse, how they will use it and why using it will improve upon the current process. It is not unusual for well considered and designed warehouses to generate first year ROIs of 100 to 400 percent. The value of the the new business processes can be determined by comparing the costs with the expected benefits.
Warehouses gather and report data that already exists.
Therefore, a warehouse cannot create more data. If a company wishes to analyze its customers by zip code but addresses are not captured by the company's systems, a warehouse will not solve the problem unless some method is found to gather this address data. In addition, if a company's data is 'dirty' in that current systems are not recording the correct information or optional fields, the warehouse will not correct that data. The warehouse is useful in identifying where data problems exist but corrections to those problems must be made in the systems that capture the data.