(FORTUNE Small Business) – The headline read WOMEN'S LEAGUE FOLDS: LACK OF SPONSORS ON OBSCURE TV CHANNEL FATAL TO THE WOMEN'S UNITED SOCCER ASSOCIATION. But nowhere in that line was the real reason the league wilted, the one and only barometer in the business of TV: ratings! The average attendance at WUSA games during the 2003 season was poor. And what was worse, its TV ratings on the PAX network were dismal, with each game grabbing a national audience in the very low six figures. Those ratings made it tough for the league to get national sponsors to open their wallets and guarantee a vital revenue stream.

No ratings. No sponsors. No cash flow. No league.

What is the barometer of success in your business? To find out, a small-business owner has to be a numbers person. No, you don't have to be a CPA or have an MBA (I'm not and I don't), but I do mean that you have to know the pulse rate that affects your financial goals.

Different businesses have different pulse rates. Magazines, for example, often measure their health by subscriber renewal rates because they demonstrate that readers enjoy the magazines enough to sign up again. The auto industry looks at the number of days of inventory on a dealer's lot so that they can plan production and monitor the popularity of a model.

During my tenure as president of the Philadelphia 76ers, there was one special pulse number that drew my attention, and I could always find it on the weekly progress report of my vice president of sales. It read "Total FSEs." Every Friday my eyes would automatically focus on that line item. One FSE, in NBA parlance, stands for one "full-season equivalent," which translates into the sale of one full-season-ticket plan of 42 games (one FSE) or the sale of two 21-game plans (one FSE) or the sale of seven six-game plans (one FSE). You get the idea.

The FSE number was crucial because the more season-ticket fans we had in the arena on game nights, the fewer tickets we had to sell to the public--which ultimately let us spend less on advertising, marketing, and sales. Since I started my five-year run with the Sixers in 1996 with fewer than 5,600 FSEs--and my goal was to fill a 20,000-seat arena--every sale of even a six-game plan was reason to celebrate. Why? Not only was the sales team helping me come closer to achieving my goal (even if it was at a tortoise's pace) but also each FSE sold brought that salesperson closer to her bonus target. The really shrewd salespeople realized that it was both easier and more lucrative to hit seven singles than to attempt to smash one homer out of the ballpark with each sales call.

My life before the Sixers was in the world of physical therapy, where I created a company called Sports Physical Therapists. The business grew into a successful chain of 40 sports-medicine centers in 11 states, and my pulse number could be found in the line item "evaluations." Yes, I wanted to know how many patients we treated each week, but more important was how many new patients we were evaluating, because it told me how much new business I had in the pipeline. If the number of new patients we were evaluating dropped, it was a sign I needed to start cutting staff to adjust for lower revenues.

To find your own pulse, ask yourself, What one number makes my heart beat with joy when I see that baby move?

Pat Croce is the author of I Feel Great and You Will Too! His new book, Lead or Get Off the Pot!, will appear in April 2004.