helps parents teach their high school and college-age kids to make better grades in school. Just last week he found me a great list, but recommended that I not roll out or even test the list until August (much to my dismay). He cares about my success.   Know Your Numbers!   Direct mail is a numbers game, pure and simple. If the numbers work in your favor, direct mail can become a cash flow profit-generating machine. If the numbers dont work in your favor, direct mail can be a cash-sucking black hole. Here are the terms you need to know: 1. Response Rate - Your response rate is the number of responses you received, divided by the number of mail pieces you sent. (Total Responses / Total Mailings)   2. Conversion Rate - Your conversion rate is the number of people who purchased from you as a result of your mailing. (Total Orders / Total Mailings)   3. Return on Investment - Return on investment is the amount of money you made on your mailing divided by your investment to do the mailing. (ROI = Net Profit / Total Investment)   4. Product Price - The selling price of your product.   5. Product Cost - All variable product costs (cost to acquire or manufacture product plus packaging and marketing costs)   6. Overhead Cost - All fixed costs (salaries, office supplies, utilities etc.)   7. Breakeven Point - The number of products or services you must sell to equal the amount of money invested to do the mailing. (Breakeven = Overhead Cost / Selling Price - Product Cost)   Direct Mail Arithmetic Rules of Thumb   Rule # 1 - Your first question in planning your campaign should be, "What must be my conversion rate at breakeven, for my assumed selling price?" Your second question should be, "Does this make sense?"   Rule # 2 - Only start a direct mail campaign if the most conservative conversion rate estimates result in a breakeven or profit. (A 1% conversion rate is considered pretty good in the direct mail world)   Rule # 3 - Caveat to rule # 2 If you have a healthy back-end it may be smart to gain customers through direct mail even at a loss.