Ever wonder how a banker can possibly know so many little facts about such a wide variety of businesses? How do they figure out, for example, that a particular company has too much overhead, or not enough equity, or that the chief executive officer's salary is too high? Well, it's not sheer genius, at least not in most cases. Rather, bankers have handy-dandy reference books that let them do a pretty good job of faking more than they know.

Recently, we received a flier announcing the new edition of one such tome, with the rather prosaic title of Annual Statement Studies. It is published by Robert Morris Associates, in Philadelphia, a highly respected professional association for bankers, and it just might contain more numbers and smaller type than the U.S. Postal Service's Zip Code directory. In one volume, RMA offers bankers -- or, for that matter, anyone willing to fork over $32.50 -- five years' worth of "trend data" on 343 separate industries. You might wonder how there can possibly be 343 industries. Perhaps you're not familiar with the "Fabrics, Narrow & Other Smallwares Mills" industry. Or the "Towing & Tugboat Services" industry. Or the "Tapes & Labels, Pressure Sensitive" industry.

RMA says it compiled data for the latest edition from financial statements of 80,000 companies. The book gives 17 commonly used ratios for each industry (note to contractors: only 14 for you), and breaks out medians and quartiles. So a quick glance at the right page might tell you, among other things, where your company stands in your industry with regard to, say, cash flow and gross profit.

Of course, it's a little disconcerting to imagine how all these medians and averages might be used by bankers. RMA, for its part, goes out of its way to discourage lenders from relying too heavily on the data; the numbers, cautions a disclaimer on page two, are presented as "general guidelines," not as "industry norms," and should be checked against other methods of evaluation.

But if bankers are like the rest of us, they may not have time for the fine print.