Starting a business is an iterative process. You have your idea, but you find that customers have a different one. So you pivot, and they pivot. And on and on the cycle goes. Eventually, you'll refine your business model to one that best serves the customers who've found you....but without a clear cut way to know you've perfected the business model, you run the risk of continuing to tweak and iterate away from the successful model.

So how do you know when you've got it right and it's time to scale?

I recently interviewed Lisa Kay Solomon, a faculty member at Singularity University and co-author of the book Design a Better Business. She specializes in using design thinking to help leaders design a better future, including a better future for your business. Solomon argues that they way to know if your model is scale-ready is to know if you're adequately doing the job your customer hired you for. "The role of design is to make the job that needs to get done doable," she says. "It's to deliver against the functional utility of that job, and if done well the design choices also deliver an emotional response."

Every purchase, services but also products, is made to help the customer do a job or do a job easier. And Solomon's answer outlines two needed tests of knowing that you've designed the right business model and it's doing the job customers hired it for: utility and emotion.

Utility asks, "Does it do the job well?" Whatever you're offering, it needs to help the customer complete the job and complete it well. Emotion asks, "Does it evoke the right feelings when it does?" Utility is not enough. We must also consider the emotions of customers when doing the job.

Solomon provides a great example: the original iPhone. "For the iPhone it helps us connect people," she says. "It helps us get access to all kinds of Apps, functionality from this computer that's now in our pocket and, particularly in the early days, the emotional job it did was give us delight. We loved our new phones. We would sleep out for our new phones. We even saved the packaging of our new phones, not by accident but because Apple designed it that way."

If you can solve both pieces, you're ready to scale. "Really understanding the job that we need to get done, not just in terms of utility, but also in terms of emotion," Solomon says. "When we have enough evidence that we're doing that, I think that's when we move forward with rolling out the product or idea."