This is a pretty common question for designers, especially from our more financially-minded clients. I would argue that creativity probably isn't what they're really trying to measure. If it is, they would first need to find a good definition for creativity, as there seem to be a variety of competing ones. Instead, most businesses probably want to measure the return on their investment in creative endeavors, i.e., design, marketing or innovation. There are ways of measuring this, though it takes a little more work perhaps than measuring ROI in, say, a new piece of manufacturing equipment. The trick to measuring return in a creative environment is to pick a metric that is meaningful to the company and project in question. Lead generation, for example, would not be an appropriate measurement for a branding advertisement. Brand awareness, on the other hand, would be appropriate. The challenge then is to translate brand awareness (or whatever other non-financial metric you use) into a financial metric. If your company provides the same basic services to a variety of clients, you will want to develop these data in order to justify the work you do. Also, be clear at the beginning of a creative project what metric will be used to judge the effectiveness of the project. I have heard even of firms that use this measurement to determine their fee for a given project. How's that for return on investment!