What Should You Include as Expenses When Calculating Return on Investment?

I've been listening to your podcast for a couple of years and I have one rental property. My question is, when you're working out your profit for your return on investment calculations, what do you include as expenses to get to that profit? Do you include your total mortgage payments? Do you also include your tax at the end of the year? Or do you just include your interest payments? And then do you exclude tax? I'm not really sure how it works and it's not very clear from how different people approach it. And yet, do you have any targets? I've read previously on your blog that you target about 10%. Has that changed for the recent market conditions or is