We are all concerned with our “productivity” these days. While writing 168 Hours, I’ve been reading through the various “Getting Things Done” literature, as well as the life-hacking websites and so forth. Some of the ideas on how to squeeze more minutes out of the day are downright hilarious. For instance, Lifehacker profiled a new iPhone application that lets you safely walk while emailing by changing the screen to be a view from the iPhone’s camera.  Yay, no more walking into leashes, toddlers or cars!

Of course, the larger questions of whether those emails really needed to get sent — or whether you need to be walking where you’re walking — are different matters. You can be the busiest person in the world, with an empty in-box because you’re so organized, but if you’re not using that time to get you where you want to be, then all that productivity is for naught.

So I’d like to propose a new definition for productivity. It’s not whether you can walk and email at the same time. It’s the proportion of your day spent on activities that are advancing you toward the career and life you want. Truly productive people spend almost 100% of their time on these activities. There’s also a corollary to this. If you’re packing in the prospects as a high-end rug salesman, but you want to be a teacher, and you are not spending any of your time on activities that are moving you toward your new career, then your productivity is 0%. Harsh? Sure. But you’re not helping anything by digging the wrong hole faster.